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GABRIEL SANCHEZ-MARTINEZ: Today
we have two guest lecturers.

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The one I invited is
Professor Peter Furth.

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00:00:29,820 --> 00:00:35,070
He's an expert on
transit signal priority.

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His own work on reliability
before time and then how people

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budget for their
travel times, he's

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a really good teacher on that.

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And he's also a bike expert.

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He's really interested
in all bicycle stuff,

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but let's not do this publicly.

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Maybe you can get
him out of this class

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and ask him something.

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00:00:54,390 --> 00:00:56,550
Then we also have-- he
dragged someone else

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in from the Netherlands who
also knows a lot about transit

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signal priorities.

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So I don't really know
what to say about him,

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but we'll find out.

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00:01:06,274 --> 00:01:07,440
Maybe you can introduce him.

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00:01:07,440 --> 00:01:09,023
PETER FURTH: Yeah,
I'll introduce him.

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Yeah, OK.

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00:01:09,810 --> 00:01:10,350
Hi all.

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00:01:10,350 --> 00:01:10,680
Thanks.

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00:01:10,680 --> 00:01:11,670
It's great to be here.

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00:01:14,540 --> 00:01:16,050
Before I get into
transit priority,

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I just want to tell you a
bit more about my background.

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So, I studied here
at MIT, and my focus

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was on public transportation.

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Then, I became a
professor at Northeastern.

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And after several
years, for one thing

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there weren't enough jobs
in public transportation.

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And my students needed more
training in traffic engineering

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because there were
more jobs in that.

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00:01:36,550 --> 00:01:39,550
But then the other thing is
that our buses were getting

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stuck in traffic all the time,
and I wanted to learn, well,

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can't we figure out a way
to make the lights turn

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green for a bus.

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I mean if we can get a
man on the moon surely

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we should be able to get the
lights to turn green for a bus.

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So I got the chance to
go to the Netherlands

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for a year, a sabbatical year.

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And almost did a
second PhD there,

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studying traffic signal
control for transit priority.

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So you have to learn all
the traffic signal control,

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00:02:10,789 --> 00:02:13,910
and then you can learn, OK, now
how do you do transit priority?

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Then I came back to
the United States,

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and it took me
several years to try

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to figure out how the Dutch
traffic signal control--

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they use different language
but it's really about the same.

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There are some differences
but it's mostly the same,

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how to say that in American
traffic signal control.

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And since then, I've
done a lot more work now

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in traffic signal control
and transit priority.

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So that's how I come here.

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My title is, Is it
help or is it hype?

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And I really mean that
because if you go to Zurich

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transit signal
priority is real help.

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I went there once on
an official visit,

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and I told the people
I was visiting,

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I came here because I've heard
it said that the trams never

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have a red light.

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He said, Yeah, well
that's just about true.

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There are some exceptions
he said, of course,

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like at the main square
there are so many trams.

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They come from
different directions

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so one tram has a red
light for another tram.

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But otherwise, there are
only one or two intersections

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in the whole city where
the trams don't just

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get a green light.

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I learned that in Portland, when
they designed their light rail

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in the 1980s, station
to station green waves

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are programmed into the
traffic signal control.

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Now it doesn't mean zero delay
because what that means is when

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a light rail train
is at a station,

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there'll be a countdown
clock for the driver.

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So there's no point in
leaving now because you're

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going to have a red light.

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But if you wait until the
appointed time to leave,

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then you will have a green
wave to the next station.

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But then we come to
applications of transit signal

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priority in the US.

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And you hear these great
pronouncements, oh, we're

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doing transit signal priority.

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But when you look into it,
there's almost no benefit.

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Sometimes they're saving
the bus two seconds

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per intersection or less.

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Often they're not
measuring at all.

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So then I have to ask, is it
really a help or is it hype?

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And so what I'm going
to tell you today

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00:04:27,810 --> 00:04:30,090
is some of the standard
ways of doing transit signal

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priority, how they
work, and how they

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don't work very [AUDIO OUT]
have to do to really

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00:04:35,620 --> 00:04:43,780
be able to have our buses or
trams have nearly zero delay.

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So before we get
into detail, why

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are we doing transit priority?

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This is a class on
public transportation

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so it probably doesn't
need a lot of argument

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but we start with a
societal objective.

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Transit offers many
benefits to society

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00:05:01,690 --> 00:05:04,510
in terms of congestion, air
quality, livable communities,

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00:05:04,510 --> 00:05:05,680
and so on.

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00:05:05,680 --> 00:05:09,610
And transit is mostly
competing with car use.

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And what transit can do is
break the vicious cycle.

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There's a vicious cycle.

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00:05:14,690 --> 00:05:16,930
This is especially strong
in developing countries.

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Whereas people get
more money, one

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of the first things they want
to buy when they have more money

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is a car.

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00:05:23,020 --> 00:05:26,920
And then with the car the
car roads become congested

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and then that
slows down transit.

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So then people don't
want to use transit

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so then they get more cars
and it just keeps going.

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If you can do priority
for a bus, then

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that breaks that cycle
and now people will say,

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I'm going to use the bus or
the train to have priority.

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00:05:44,930 --> 00:05:51,770
And then having priority for
transit makes a lot of sense

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00:05:51,770 --> 00:05:58,400
because the tradition in Boston
has been a very extreme all

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or nothing priority.

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We know one way to
give transit priority.

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00:06:02,690 --> 00:06:04,970
Total grade separation.

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00:06:04,970 --> 00:06:10,460
We build a subway, and they're
protected from congestion.

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So we know how to do
the $2 billion priority

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00:06:13,930 --> 00:06:17,170
and we also know the other
extreme, which is nothing.

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00:06:17,170 --> 00:06:18,910
Buses you're welcome
to use our roads.

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00:06:18,910 --> 00:06:21,610
I mean when the light turns
green everybody else can go,

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I guess you can too.

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It doesn't make sense to
only have those two extremes.

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And that's what the
city of Zurich did.

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The main planners for Zurich
wanted to build a subway.

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This was in the 1970s.

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Big cities that didn't
have subway systems

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then were building them.

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But the citizens said, no,
spend a tenth of the money--

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because subways are
incredibly expensive,

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00:06:47,560 --> 00:06:49,660
spend about a
tenth of that money

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00:06:49,660 --> 00:06:53,680
to give our trams
priority, and then we

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00:06:53,680 --> 00:06:56,270
don't have to walk
down in the basement.

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00:06:56,270 --> 00:06:59,830
And instead we like how
the trams are right.

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00:06:59,830 --> 00:07:01,900
It's almost like an
extension of the sidewalk.

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00:07:01,900 --> 00:07:05,140
You just step on,
ride, step off.

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00:07:05,140 --> 00:07:08,800
So it makes sense to have
some means of priority that's

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00:07:08,800 --> 00:07:11,360
in between all or nothing.

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00:07:11,360 --> 00:07:13,380
And we have two ways
of doing priority.

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It's priority in space.

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That means you give the buses
or the trams their own lane,

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their own space.

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And then there's
priority at time,

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which comes at traffic signals.

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Priority, it's easy to see what
it means to a transit user.

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It means you get a faster
ride and a more reliable ride.

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So it saves you time.

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The reliability means it also
saves you in buffer time.

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But it's important to know
what transit priority means

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to a transit operator.

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The savings in time
means they might

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be able to run their route with
fewer vehicles and less labor.

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00:07:54,170 --> 00:07:56,540
And the improved
reliability means

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they don't have to have
as much recovery time.

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00:08:01,100 --> 00:08:07,800
So in Portland they had a
case at Tri-Mat Line 12.

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The transit priority they put in
didn't reduce the running time

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that much.

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00:08:11,250 --> 00:08:13,920
But it reduced the
variability of running time

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so much that they were
able to reduce the cycle

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00:08:18,810 --> 00:08:22,140
time by 11 minutes.

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00:08:22,140 --> 00:08:24,930
And if you reduce the cycle
time by 11 minutes on a route

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that runs every 11
minutes or every--

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00:08:27,360 --> 00:08:31,730
then you save one
bus and one operator.

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And that lowers your
cost tremendously.

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So priority is important
for passengers,

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00:08:37,260 --> 00:08:40,690
it's important for the operator.

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00:08:40,690 --> 00:08:48,770
And I told you I studied traffic
signals in the Netherlands

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and it was in the context
of transit priority--

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00:08:53,660 --> 00:08:55,590
how can we make
transit service better?

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00:08:55,590 --> 00:09:01,760
So here you have two
graphs, each line

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00:09:01,760 --> 00:09:04,310
represents the
trajectory of a vehicle.

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00:09:04,310 --> 00:09:05,810
On the bottom is space.

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00:09:05,810 --> 00:09:09,200
We're going from station
CL across to station S.

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00:09:09,200 --> 00:09:12,260
And on the vertical axis is
how far off schedule are we?

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So if you're at the
0 line, that means

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00:09:14,930 --> 00:09:17,790
you're perfectly on schedule.

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00:09:17,790 --> 00:09:24,600
And as you go above the line,
you're earlier and earlier.

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00:09:24,600 --> 00:09:27,720
And as you go below the
line your later and later.

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00:09:27,720 --> 00:09:30,810
So this is what the
operation was, kind of

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00:09:30,810 --> 00:09:33,510
if you just let it be.

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00:09:33,510 --> 00:09:35,642
The buses will start
pretty close to on time

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00:09:35,642 --> 00:09:38,100
but they got later and later
and later, and the spread just

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00:09:38,100 --> 00:09:39,391
gets worse and worse and worse.

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00:09:39,391 --> 00:09:40,680
This is nothing new.

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00:09:40,680 --> 00:09:42,690
If you know about
transit service

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00:09:42,690 --> 00:09:47,700
you know how there's
these random shocks

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00:09:47,700 --> 00:09:48,617
could make a bus late.

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00:09:48,617 --> 00:09:51,033
And once you're late you become
later and later and later.

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00:09:51,033 --> 00:09:53,320
And once you're early you
become earlier and earlier

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00:09:53,320 --> 00:09:53,850
and earlier.

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00:09:53,850 --> 00:09:58,544
But here they put in
a system with priority

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at the traffic lights.

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00:09:59,460 --> 00:10:02,130
And it's conditional priority.

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00:10:02,130 --> 00:10:06,630
If the bus is early, no priority
for you but if the bus is late,

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00:10:06,630 --> 00:10:09,090
we're going to give
very aggressive priority

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00:10:09,090 --> 00:10:11,880
so that bus can cruise right
through the intersection.

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00:10:11,880 --> 00:10:14,970
So if the average time to
get through an intersection

207
00:10:14,970 --> 00:10:18,000
is let's say half a
minute, but with priority

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00:10:18,000 --> 00:10:20,700
that's going to be 10
seconds and without priority

209
00:10:20,700 --> 00:10:22,320
that's going to be 50 seconds.

210
00:10:22,320 --> 00:10:26,760
That's a 40 second
difference that I

211
00:10:26,760 --> 00:10:30,390
can make my bus 20 seconds
later by not giving it priority.

212
00:10:30,390 --> 00:10:33,960
I can make my bus 50 seconds
earlier by giving it priority.

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00:10:33,960 --> 00:10:36,990
So with that you see how
much tighter the lines are,

214
00:10:36,990 --> 00:10:40,920
how much better
the reliability is

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00:10:40,920 --> 00:10:44,970
because the priority system
is able to keep those buses

216
00:10:44,970 --> 00:10:45,910
right on schedule.

217
00:10:45,910 --> 00:10:46,110
Yeah.

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00:10:46,110 --> 00:10:48,109
AUDIENCE: [INAUDIBLE]
people driving on the road

219
00:10:48,109 --> 00:10:49,975
would have to use
that traffic light

220
00:10:49,975 --> 00:10:52,584
and they know it normally
takes them 30 seconds and all

221
00:10:52,584 --> 00:10:56,210
of a sudden it's 50 seconds
or is this a separate thing?

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00:10:56,210 --> 00:10:59,300
PETER FURTH: No,
this is not let's

223
00:10:59,300 --> 00:11:01,280
hold the light red extra long.

224
00:11:01,280 --> 00:11:04,550
This is just we won't
give priority, that's all.

225
00:11:04,550 --> 00:11:08,480
So, yeah when I say we
won't give priority,

226
00:11:08,480 --> 00:11:11,130
I'm not talking about holding.

227
00:11:11,130 --> 00:11:13,170
So we're not deliberately
holding the light red.

228
00:11:13,170 --> 00:11:16,920
It's just, if the bus arrives in
the light is green, OK bus you

229
00:11:16,920 --> 00:11:17,670
get to go through.

230
00:11:17,670 --> 00:11:19,381
But if you arrive
when it's red, I'm

231
00:11:19,381 --> 00:11:21,630
not going to hurry up and
turn the light green for you

232
00:11:21,630 --> 00:11:22,650
if you're early.

233
00:11:22,650 --> 00:11:24,358
I'm only going to do
that if you're late.

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00:11:27,430 --> 00:11:32,050
And priority makes
transit more competitive

235
00:11:32,050 --> 00:11:36,340
because after all if transit
has to stop to pick people up,

236
00:11:36,340 --> 00:11:40,060
that slows it down, you have to
walk to get to the station that

237
00:11:40,060 --> 00:11:41,350
adds more travel time.

238
00:11:41,350 --> 00:11:43,330
How can we compete with car?

239
00:11:43,330 --> 00:11:48,537
Well one way we can compete is
we can give transit priority

240
00:11:48,537 --> 00:11:49,870
and it makes it more acceptable.

241
00:11:49,870 --> 00:11:52,180
And because I got late, I
get don't get to tell you

242
00:11:52,180 --> 00:11:55,120
the story about my great aunt.

243
00:11:55,120 --> 00:11:58,840
So there are different
levels of priority.

244
00:11:58,840 --> 00:12:00,940
One of the things you'll
often hear if you ever

245
00:12:00,940 --> 00:12:03,040
hear a presentation about
priority, they'll say,

246
00:12:03,040 --> 00:12:05,170
it's not preemption.

247
00:12:05,170 --> 00:12:09,520
Preemption is a technical term
in traffic signal control,

248
00:12:09,520 --> 00:12:13,770
and preemption is what
we'll do for a fire truck.

249
00:12:13,770 --> 00:12:18,150
And that just means oh,
preempt the signal, just stop.

250
00:12:18,150 --> 00:12:22,530
Every conflicting movement
goes to yellow, goes to red,

251
00:12:22,530 --> 00:12:25,820
and we just stop everything so
the fire truck can go through.

252
00:12:25,820 --> 00:12:29,160
And by the way the street
that the fire truck is on we

253
00:12:29,160 --> 00:12:33,952
don't turn that one red, we
would make that one green.

254
00:12:33,952 --> 00:12:35,910
It's not like we ask
everybody to pull over out

255
00:12:35,910 --> 00:12:37,118
of the way of the fire truck.

256
00:12:37,118 --> 00:12:39,630
We ask everybody just keep
driving, go, go, go, go, go,

257
00:12:39,630 --> 00:12:40,170
go, go.

258
00:12:40,170 --> 00:12:41,940
Give them green
wave, go, go, go,

259
00:12:41,940 --> 00:12:44,400
and then the fire
engine comes along.

260
00:12:44,400 --> 00:12:45,930
So that's preemption.

261
00:12:45,930 --> 00:12:47,310
We do that for fire engines.

262
00:12:47,310 --> 00:12:52,860
And we do that for trains
because trains can't brake.

263
00:12:52,860 --> 00:12:56,280
You get a train coming along
at 40, 50 miles an hour,

264
00:12:56,280 --> 00:12:58,320
trains-- that steel
wheel on steel rail,

265
00:12:58,320 --> 00:13:01,060
they can't brake very quickly.

266
00:13:01,060 --> 00:13:05,580
So we will preempt
a light for a train.

267
00:13:05,580 --> 00:13:08,340
So priority is something
short of preemption.

268
00:13:08,340 --> 00:13:11,970
For instance, with
transit priority

269
00:13:11,970 --> 00:13:14,205
we will not cut off
a pedestrian phase.

270
00:13:17,470 --> 00:13:19,320
There's a certain
clearance for pedestrians

271
00:13:19,320 --> 00:13:20,940
to be able to cross the street.

272
00:13:20,940 --> 00:13:23,250
You've seen the
countdown signals.

273
00:13:23,250 --> 00:13:25,990
So for a fire engine
they'll just--

274
00:13:25,990 --> 00:13:30,710
it could be 15, 14, 0.

275
00:13:30,710 --> 00:13:34,190
But we won't do
that for transit.

276
00:13:34,190 --> 00:13:41,060
And preemption it doesn't
think a moment about the impact

277
00:13:41,060 --> 00:13:42,520
on the other traffic.

278
00:13:42,520 --> 00:13:44,286
We got to save a life.

279
00:13:44,286 --> 00:13:46,160
Somebody's life is at
stake, somebody's house

280
00:13:46,160 --> 00:13:48,020
is burning down,
and there's a train

281
00:13:48,020 --> 00:13:50,160
coming that would kill
everybody in its way.

282
00:13:50,160 --> 00:13:53,120
So when it comes to saving a
life you don't worry about,

283
00:13:53,120 --> 00:13:56,540
is it costing people a few
extra seconds, minutes of time?

284
00:13:56,540 --> 00:13:59,090
But transit priority
we're going to give

285
00:13:59,090 --> 00:14:02,390
priority to transit vehicle
every five minutes every,

286
00:14:02,390 --> 00:14:03,650
three minutes.

287
00:14:03,650 --> 00:14:05,330
You can't be
completely disrupting

288
00:14:05,330 --> 00:14:08,300
and screwing up traffic
every three minutes.

289
00:14:08,300 --> 00:14:11,420
You have to think about
how it affects others.

290
00:14:11,420 --> 00:14:14,424
So there are some
standard tactics.

291
00:14:14,424 --> 00:14:16,340
The main ones I'll talk
about are listed here.

292
00:14:16,340 --> 00:14:18,920
Green extension and
early green, but I'll

293
00:14:18,920 --> 00:14:22,640
also talked about some
more intelligent tactics

294
00:14:22,640 --> 00:14:24,740
and some ways of
changing the background.

295
00:14:27,450 --> 00:14:31,080
So let's look at the most
popular tactic, which

296
00:14:31,080 --> 00:14:33,330
is green extension.

297
00:14:33,330 --> 00:14:37,140
Green extension means the
street that the bus is on,

298
00:14:37,140 --> 00:14:38,870
the light is green.

299
00:14:38,870 --> 00:14:42,440
It's about to turn
yellow, but we detect,

300
00:14:42,440 --> 00:14:45,950
oh, there's a bus coming and
it's only 12 seconds away.

301
00:14:45,950 --> 00:14:48,950
All right, then we'll
just delay turning yellow.

302
00:14:48,950 --> 00:14:51,350
We'll just extend the
green, and then the bus

303
00:14:51,350 --> 00:14:52,940
will come right through.

304
00:14:52,940 --> 00:14:57,360
And then the light can
turn yellow and turn red.

305
00:14:57,360 --> 00:15:02,360
So that offers, as I have
there on the slide, a very

306
00:15:02,360 --> 00:15:07,680
large benefit to the buses
who take advantage of this.

307
00:15:07,680 --> 00:15:11,510
I mean, because the bus who
gets the green extension, that's

308
00:15:11,510 --> 00:15:14,090
the bus that if they
didn't get that extension

309
00:15:14,090 --> 00:15:17,060
they would arrive right
near the beginning of red.

310
00:15:17,060 --> 00:15:19,480
And they'd have the longest
wait of anybody in the cycle.

311
00:15:19,480 --> 00:15:22,430
They'd have to wait whole red
period until they can finally

312
00:15:22,430 --> 00:15:23,700
go on.

313
00:15:23,700 --> 00:15:25,730
So if the red period
is 70 seconds long,

314
00:15:25,730 --> 00:15:28,810
you just save that
bus about 70 seconds.

315
00:15:28,810 --> 00:15:32,170
So it's a very large benefit,
but it's a benefit only

316
00:15:32,170 --> 00:15:33,910
to a few buses.

317
00:15:33,910 --> 00:15:37,690
Because which buses get
to enjoy that benefit?

318
00:15:37,690 --> 00:15:42,370
Only the ones arriving during
the first few seconds of red.

319
00:15:42,370 --> 00:15:45,730
Let's say you're willing to give
a 15 second green extension,

320
00:15:45,730 --> 00:15:49,720
then any bus arriving in the
first 15 seconds of red that

321
00:15:49,720 --> 00:15:50,950
gets a benefit.

322
00:15:50,950 --> 00:15:53,680
But if the cycle
is 100 seconds long

323
00:15:53,680 --> 00:15:56,500
and buses arrive at random,
well that's only 15%

324
00:15:56,500 --> 00:15:59,000
of the arrivals that
are in that window.

325
00:15:59,000 --> 00:16:02,740
So green extension
is a large benefit

326
00:16:02,740 --> 00:16:05,410
but to a small number of buses.

327
00:16:05,410 --> 00:16:08,470
And we can model that
benefit this way.

328
00:16:11,444 --> 00:16:16,520
On the horizontal axis
is time in the cycle.

329
00:16:16,520 --> 00:16:23,360
And on the vertical
axis, I have arrivals

330
00:16:23,360 --> 00:16:25,760
and so you have cumulative
vehicles arriving.

331
00:16:25,760 --> 00:16:29,890
And then the red lines
going across, that's--

332
00:16:29,890 --> 00:16:31,156
you're raising your hand?

333
00:16:31,156 --> 00:16:31,520
AUDIENCE: I have a question.

334
00:16:31,520 --> 00:16:32,270
PETER FURTH: Yeah.

335
00:16:32,270 --> 00:16:33,979
AUDIENCE: So but
now that you said,

336
00:16:33,979 --> 00:16:36,020
it's a large benefit to
a small number of buses--

337
00:16:36,020 --> 00:16:36,780
PETER FURTH: Yeah.

338
00:16:36,780 --> 00:16:39,440
AUDIENCE: --per intersection
because if the whole bus run

339
00:16:39,440 --> 00:16:45,080
is 10-20 signal
intersection, then over time

340
00:16:45,080 --> 00:16:48,070
the probability of every single
bus enjoying that and every bus

341
00:16:48,070 --> 00:16:49,441
that runs [INAUDIBLE]

342
00:16:49,441 --> 00:16:50,190
PETER FURTH: Sure.

343
00:16:50,190 --> 00:16:50,815
AUDIENCE: Yeah.

344
00:16:50,815 --> 00:16:53,630
You say it's only 15% of
buses, it's actually a lot more

345
00:16:53,630 --> 00:16:54,260
and it's--

346
00:16:54,260 --> 00:16:57,135
PETER FURTH: So let's say 15%
of bus arrivals at a signal.

347
00:16:57,135 --> 00:16:58,260
AUDIENCE: At a signal but--

348
00:16:58,260 --> 00:16:58,410
PETER FURTH: Yeah.

349
00:16:58,410 --> 00:16:59,260
AUDIENCE: --over
a lot of signals?

350
00:16:59,260 --> 00:17:00,100
PETER FURTH: Yeah.

351
00:17:00,100 --> 00:17:00,600
Yeah.

352
00:17:00,600 --> 00:17:03,490
If I'm running a route in which
I'm going through 20 signals

353
00:17:03,490 --> 00:17:06,704
and I'm going to get the benefit
of 15% of them on average,

354
00:17:06,704 --> 00:17:08,329
I'll get that benefit,
well, that would

355
00:17:08,329 --> 00:17:10,670
be three times 15% of 20.

356
00:17:10,670 --> 00:17:11,810
Yeah.

357
00:17:11,810 --> 00:17:17,380
So the red lines here
represent the time

358
00:17:17,380 --> 00:17:18,940
that a person is in the queue.

359
00:17:18,940 --> 00:17:23,619
So like the car arrival--

360
00:17:23,619 --> 00:17:25,720
here's arrival
number one and then

361
00:17:25,720 --> 00:17:27,369
this line is the
departure curve.

362
00:17:27,369 --> 00:17:30,430
Cars arrive at a
relatively slow rate,

363
00:17:30,430 --> 00:17:32,830
let's say one car
every five seconds.

364
00:17:32,830 --> 00:17:36,250
And they pull out at a much
faster rate, say one car

365
00:17:36,250 --> 00:17:38,300
every two seconds.

366
00:17:38,300 --> 00:17:43,690
So each horizontal line
represents a certain vehicle.

367
00:17:43,690 --> 00:17:47,950
So let's say the vehicle
number two arrives here.

368
00:17:47,950 --> 00:17:50,950
And vehicle number two
doesn't depart until here.

369
00:17:50,950 --> 00:17:53,830
So that horizontal line
is the waiting time

370
00:17:53,830 --> 00:17:54,790
of vehicle number two.

371
00:17:54,790 --> 00:17:58,570
So in this representation,
horizontal distance

372
00:17:58,570 --> 00:18:00,190
is waiting time.

373
00:18:00,190 --> 00:18:04,570
So for the bus with
a green extension,

374
00:18:04,570 --> 00:18:08,680
instead of red starting
at times throw,

375
00:18:08,680 --> 00:18:11,290
the red actually doesn't
start until here.

376
00:18:11,290 --> 00:18:15,130
So a bus that would have
arrived and had been delayed,

377
00:18:15,130 --> 00:18:16,690
now those buses aren't--

378
00:18:16,690 --> 00:18:19,690
buses that arrive after
the extension time

379
00:18:19,690 --> 00:18:20,980
still are delayed.

380
00:18:20,980 --> 00:18:28,930
So the possibility
for delay, which

381
00:18:28,930 --> 00:18:31,970
is represented by the red
area, there is less of it.

382
00:18:31,970 --> 00:18:37,450
And you find the average
horizontal length

383
00:18:37,450 --> 00:18:39,100
between these lines.

384
00:18:39,100 --> 00:18:43,450
And then you do a
little bit of geometry.

385
00:18:43,450 --> 00:18:48,350
And we find that the expected
delay in the first case,

386
00:18:48,350 --> 00:18:51,200
this is the standard
delay for cars,

387
00:18:51,200 --> 00:18:54,890
has to do with the length of
the [AUDIO OUT] car, the cycle

388
00:18:54,890 --> 00:18:59,090
length, C, and the ratio
of the arrival rate

389
00:18:59,090 --> 00:19:02,090
to the discharge
rate, that's v over s.

390
00:19:02,090 --> 00:19:04,340
And when we put in
a green extension,

391
00:19:04,340 --> 00:19:08,430
we have that same term
minus this term here.

392
00:19:08,430 --> 00:19:10,670
And I give that the
name the priority push.

393
00:19:10,670 --> 00:19:18,190
So that's the reduction in
delay thanks to green extension.

394
00:19:18,190 --> 00:19:20,680
And that reduction
in delay has to do

395
00:19:20,680 --> 00:19:23,710
with how long an extension
are you willing to give.

396
00:19:23,710 --> 00:19:26,320
In some places though
they say, well, I'm

397
00:19:26,320 --> 00:19:28,480
willing to extend
for 10 seconds.

398
00:19:28,480 --> 00:19:30,700
In Toronto, they often
say, I'm willing to extend

399
00:19:30,700 --> 00:19:33,050
for 30 seconds.

400
00:19:33,050 --> 00:19:37,100
So it depends on how
long is your extension.

401
00:19:37,100 --> 00:19:40,280
But it also depends a lot
on how long is your red

402
00:19:40,280 --> 00:19:42,750
and how long is your cycle.

403
00:19:42,750 --> 00:19:45,680
So just so you can
have some numbers of--

404
00:19:45,680 --> 00:19:46,306
Yeah.

405
00:19:46,306 --> 00:19:46,972
AUDIENCE: Sorry.

406
00:19:46,972 --> 00:19:57,390
[INAUDIBLE] why is the order
[INAUDIBLE] assigned to that?

407
00:19:57,390 --> 00:20:02,220
PETER FURTH: So this line here?

408
00:20:02,220 --> 00:20:02,844
AUDIENCE: Mhm.

409
00:20:02,844 --> 00:20:03,510
PETER FURTH: OK.

410
00:20:03,510 --> 00:20:09,910
So that represents the
cumulative departing cars, OK?

411
00:20:09,910 --> 00:20:13,309
So at a certain point in
time, the light turns green

412
00:20:13,309 --> 00:20:14,600
and then the first car departs.

413
00:20:14,600 --> 00:20:17,420
The second car doesn't depart
until about two seconds later.

414
00:20:17,420 --> 00:20:19,110
The cars follow one another.

415
00:20:19,110 --> 00:20:24,560
So this line has a
slope of about one car

416
00:20:24,560 --> 00:20:27,170
every two seconds
as they depart.

417
00:20:27,170 --> 00:20:28,500
This is as they arrive.

418
00:20:28,500 --> 00:20:34,160
It's maybe one car every five,
six, seven, eight seconds, OK?

419
00:20:34,160 --> 00:20:36,890
And where the two
lines meet, that

420
00:20:36,890 --> 00:20:40,610
means the last car in
the queue is now gone.

421
00:20:40,610 --> 00:20:48,350
And after that, as cars arrive
and depart without any joining

422
00:20:48,350 --> 00:20:51,970
acuity, just go through.

423
00:20:51,970 --> 00:20:55,420
So to put some numbers
on that priority push,

424
00:20:55,420 --> 00:20:58,420
let's consider a sort
of typical intersection

425
00:20:58,420 --> 00:21:00,610
with a cycle length
of 100 seconds,

426
00:21:00,610 --> 00:21:04,810
50 seconds of red
time, and the v over s.

427
00:21:04,810 --> 00:21:08,260
That v over s term is such
that the degree of saturation

428
00:21:08,260 --> 00:21:11,600
is 85% which that's
pretty typical.

429
00:21:11,600 --> 00:21:14,170
So this shows how the
priority push varies

430
00:21:14,170 --> 00:21:15,700
with the green extension.

431
00:21:15,700 --> 00:21:18,310
The longer an extension
you're willing to give

432
00:21:18,310 --> 00:21:19,760
the more of a priority push.

433
00:21:19,760 --> 00:21:22,640
But notice they're not
equal to each other.

434
00:21:22,640 --> 00:21:25,840
For instance, when the green
extension is 15 seconds

435
00:21:25,840 --> 00:21:29,180
that gives me a priority
push of about eight seconds.

436
00:21:29,180 --> 00:21:35,740
So often if anybody does try to
describe the priority tactics

437
00:21:35,740 --> 00:21:38,000
they're using, they'll say
something like, oh, when we

438
00:21:38,000 --> 00:21:41,279
give 15 second green extension.

439
00:21:41,279 --> 00:21:43,570
Well that doesn't mean it's
going to speed the buses up

440
00:21:43,570 --> 00:21:46,180
by 15 seconds.

441
00:21:46,180 --> 00:21:50,470
In this case, how it
affects each individual bus

442
00:21:50,470 --> 00:21:56,290
varies but on average that will
reduce the delay of buses--

443
00:21:56,290 --> 00:21:59,710
this is averaged over all
buses, reduce the delay

444
00:21:59,710 --> 00:22:01,330
by eight seconds.

445
00:22:01,330 --> 00:22:04,870
And then it has a lot to
do also with the cycling.

446
00:22:04,870 --> 00:22:08,680
So let's again consider
100 second cycle,

447
00:22:08,680 --> 00:22:10,210
degree saturation 85.

448
00:22:10,210 --> 00:22:14,080
This time hold the
green extension period

449
00:22:14,080 --> 00:22:15,760
fixed to 15 seconds.

450
00:22:15,760 --> 00:22:20,080
And look at different
amounts of red time.

451
00:22:20,080 --> 00:22:24,130
So if you're red
time is low, that's

452
00:22:24,130 --> 00:22:26,200
like the buses on
the through road that

453
00:22:26,200 --> 00:22:27,465
gets green most of the time.

454
00:22:27,465 --> 00:22:30,090
We're green most of the time and
only a small part of the cycle

455
00:22:30,090 --> 00:22:31,720
is for the cross street.

456
00:22:31,720 --> 00:22:34,750
Well then the priority
push is pretty small,

457
00:22:34,750 --> 00:22:36,460
only about five seconds.

458
00:22:36,460 --> 00:22:41,170
But if the red time is long,
if it's 100 second cycle

459
00:22:41,170 --> 00:22:45,640
and the light is red for you
90 out of those 100 seconds,

460
00:22:45,640 --> 00:22:51,850
well then getting pushed ahead
15 seconds will save you a lot.

461
00:22:51,850 --> 00:22:57,460
Now when is the light red
for 90 out of 100 seconds?

462
00:22:57,460 --> 00:23:00,190
Under what kind of
traffic movement

463
00:23:00,190 --> 00:23:03,340
would it be that is
red almost all the time

464
00:23:03,340 --> 00:23:04,390
with a very short green?

465
00:23:04,390 --> 00:23:09,201
AUDIENCE: Maybe like a city
center pedestrian plaza?

466
00:23:09,201 --> 00:23:10,450
PETER FURTH: No, probably not.

467
00:23:10,450 --> 00:23:12,444
Because if you only
give the cars 10 seconds

468
00:23:12,444 --> 00:23:14,110
you just can't get
much traffic through.

469
00:23:14,110 --> 00:23:14,610
Yeah?

470
00:23:14,610 --> 00:23:16,240
AUDIENCE: D street
in South Boston.

471
00:23:16,240 --> 00:23:18,250
PETER FURTH: Ho, ho,
ho, ho, ho you got it.

472
00:23:18,250 --> 00:23:19,390
You got it.

473
00:23:19,390 --> 00:23:22,303
But that's not a typical case.

474
00:23:22,303 --> 00:23:26,584
AUDIENCE: The cross streets
of a major thoroughfare?

475
00:23:26,584 --> 00:23:28,000
PETER FURTH: So
the cross streets,

476
00:23:28,000 --> 00:23:30,925
even they get more
like 25-30 seconds.

477
00:23:30,925 --> 00:23:32,830
AUDIENCE: Like a
protected class.

478
00:23:32,830 --> 00:23:34,870
PETER FURTH: A left
turn, that's it.

479
00:23:34,870 --> 00:23:37,450
This is the one that
really, really could

480
00:23:37,450 --> 00:23:40,990
benefit from a green extension.

481
00:23:40,990 --> 00:23:44,830
So right next to Northeastern
is Ruggles Station,

482
00:23:44,830 --> 00:23:47,710
and you got all these
buses making left turns.

483
00:23:47,710 --> 00:23:50,840
And if they don't
make it, uh sorry,

484
00:23:50,840 --> 00:23:57,600
120 second cycle,
100 seconds of red.

485
00:23:57,600 --> 00:24:02,830
So that's a situation where
a green extension would be--

486
00:24:02,830 --> 00:24:07,550
it's valuable in all these cases
but it's especially valuable

487
00:24:07,550 --> 00:24:11,150
when there's a
really long red time.

488
00:24:11,150 --> 00:24:13,550
So I'm glad you
mentioned D Street.

489
00:24:13,550 --> 00:24:15,080
I'll be talking about D Street.

490
00:24:15,080 --> 00:24:17,300
All right.

491
00:24:17,300 --> 00:24:20,570
OK, how do we do detection?

492
00:24:20,570 --> 00:24:24,514
Technically to detect the
bus, it's almost trivial.

493
00:24:24,514 --> 00:24:26,180
There's so many
different ways to do it.

494
00:24:30,370 --> 00:24:34,870
I'll say something about
technologies, but where

495
00:24:34,870 --> 00:24:36,130
we want to detect the bus.

496
00:24:36,130 --> 00:24:39,280
So we want to have a check-in
detector so the bus reports in.

497
00:24:39,280 --> 00:24:40,330
Hello, I'm a bus.

498
00:24:40,330 --> 00:24:42,840
Can you give me priority?

499
00:24:42,840 --> 00:24:44,670
And there is a trade-off.

500
00:24:44,670 --> 00:24:47,700
The sooner we know,
the better because then

501
00:24:47,700 --> 00:24:50,460
we can prepare for it and
get that light to be red.

502
00:24:50,460 --> 00:24:54,810
But if you tell me
two minutes in advance

503
00:24:54,810 --> 00:24:59,010
there's a bus coming, bus travel
time is not deterministic.

504
00:24:59,010 --> 00:24:59,510
All right?

505
00:24:59,510 --> 00:25:03,680
So there might be stops in
between and random dwell time.

506
00:25:03,680 --> 00:25:05,770
There might be other
traffic signals in between.

507
00:25:05,770 --> 00:25:11,210
So usually we want
our check-in to be

508
00:25:11,210 --> 00:25:15,260
as far away as can be but no
farther than the next stop

509
00:25:15,260 --> 00:25:17,810
or the next intersection
so there's a pretty

510
00:25:17,810 --> 00:25:22,070
deterministic travel time.

511
00:25:22,070 --> 00:25:24,460
We also want there to
be a check-out detector.

512
00:25:24,460 --> 00:25:27,320
Some systems omit the
check-out detector.

513
00:25:27,320 --> 00:25:30,750
So if you omit the
check-out detector,

514
00:25:30,750 --> 00:25:32,520
here's how inefficient you are.

515
00:25:32,520 --> 00:25:34,270
You say, oh, there's
a bus coming.

516
00:25:34,270 --> 00:25:36,760
I'll give it a 15
second extension.

517
00:25:36,760 --> 00:25:38,860
The bus goes through
after three seconds,

518
00:25:38,860 --> 00:25:41,754
and you still hold the
light green for the full 15.

519
00:25:41,754 --> 00:25:42,920
That doesn't make any sense.

520
00:25:42,920 --> 00:25:44,830
So have a check-out detector.

521
00:25:44,830 --> 00:25:46,780
As soon as the
bus hits that, you

522
00:25:46,780 --> 00:25:50,710
cancel the extension request,
let the light turn yellow.

523
00:25:53,520 --> 00:25:57,040
The traditional
technology for extension

524
00:25:57,040 --> 00:26:00,610
is we bury in the
ground a loop--

525
00:26:00,610 --> 00:26:03,100
not just a dumb loop
of cable but a loop

526
00:26:03,100 --> 00:26:04,460
that acts like an antenna.

527
00:26:04,460 --> 00:26:09,310
So the bus is coming along,
giving along a very low energy

528
00:26:09,310 --> 00:26:09,820
signal.

529
00:26:09,820 --> 00:26:10,690
I'm a bus.

530
00:26:10,690 --> 00:26:14,800
I'm bus number 2356 so you
can check my ID to make sure

531
00:26:14,800 --> 00:26:18,580
that this is not a stolen unit.

532
00:26:18,580 --> 00:26:20,320
And it could give
off some information

533
00:26:20,320 --> 00:26:23,290
like, I'm turning left
so I need the left arrow.

534
00:26:23,290 --> 00:26:27,190
There's another bus route coming
along that's going straight.

535
00:26:27,190 --> 00:26:29,920
So that's one way of doing it.

536
00:26:29,920 --> 00:26:36,640
Nowadays, we'll be doing it with
GPS and basically cell phone

537
00:26:36,640 --> 00:26:38,280
technology, texting.

538
00:26:38,280 --> 00:26:41,809
The bus sets up text messages
with the controller and says,

539
00:26:41,809 --> 00:26:43,850
here are my coordinates,
here are my coordinates,

540
00:26:43,850 --> 00:26:47,740
and just keep sending
essentially the packets of cell

541
00:26:47,740 --> 00:26:50,800
data like text messages.

542
00:26:50,800 --> 00:26:55,150
And then we know where the bus
is, and we can take action.

543
00:26:57,660 --> 00:26:59,960
So I can skip that.

544
00:26:59,960 --> 00:27:04,190
So one difficulty
of giving priority

545
00:27:04,190 --> 00:27:07,240
is, well, what if
there's a near side stop?

546
00:27:07,240 --> 00:27:11,030
If you looked at
locating stops for buses,

547
00:27:11,030 --> 00:27:14,360
you know there's a basic
choice between the near side,

548
00:27:14,360 --> 00:27:18,420
the upstream side
intersection or the far side.

549
00:27:18,420 --> 00:27:20,180
Well, if you're
on the near side,

550
00:27:20,180 --> 00:27:23,300
remember stop dwell
time is random.

551
00:27:23,300 --> 00:27:25,280
So I don't even want
to check the bus

552
00:27:25,280 --> 00:27:27,590
in until it's left the stop.

553
00:27:27,590 --> 00:27:29,330
Well, that means
my check-in point

554
00:27:29,330 --> 00:27:31,310
is going to be awfully close.

555
00:27:31,310 --> 00:27:31,820
So what?

556
00:27:31,820 --> 00:27:35,230
I'm going to find out two
seconds before the bus comes

557
00:27:35,230 --> 00:27:37,250
that a bus is coming?

558
00:27:37,250 --> 00:27:39,840
If you only have two
seconds advance notice,

559
00:27:39,840 --> 00:27:43,654
how long a green
extension can you give?

560
00:27:43,654 --> 00:27:44,650
AUDIENCE: Two seconds.

561
00:27:44,650 --> 00:27:45,691
PETER FURTH: Two seconds.

562
00:27:45,691 --> 00:27:46,900
Think about it.

563
00:27:46,900 --> 00:27:49,600
You can't give a
15 second extension

564
00:27:49,600 --> 00:27:53,500
if you're only detecting the
bus two seconds early, right?

565
00:27:53,500 --> 00:27:56,290
If I was going to end
the green at time--

566
00:27:56,290 --> 00:27:58,980
let's just pick a
number at time 50

567
00:27:58,980 --> 00:28:02,580
and I said, oh, I'm willing
to wait till time 65.

568
00:28:02,580 --> 00:28:05,700
But I don't know when the
bus is there until time 63,

569
00:28:05,700 --> 00:28:08,290
how would I know to
extend the green?

570
00:28:08,290 --> 00:28:08,790
Yeah.

571
00:28:08,790 --> 00:28:13,270
You cannot give a green
extension longer than

572
00:28:13,270 --> 00:28:16,310
the advance notice
that you have.

573
00:28:16,310 --> 00:28:19,240
So this is a killer.

574
00:28:19,240 --> 00:28:19,740
Yeah.

575
00:28:19,740 --> 00:28:21,948
AUDIENCE: I'm just curious
about the actual mechanics

576
00:28:21,948 --> 00:28:23,170
of the signal extension.

577
00:28:23,170 --> 00:28:23,410
PETER FURTH: Yeah.

578
00:28:23,410 --> 00:28:24,785
AUDIENCE: Is this
a signal you're

579
00:28:24,785 --> 00:28:27,370
sending to just that one
traffic intersection or are you

580
00:28:27,370 --> 00:28:29,330
sending a signal to some
central control that's

581
00:28:29,330 --> 00:28:31,690
controlling the whole
city's traffic lights?

582
00:28:31,690 --> 00:28:33,070
PETER FURTH: A single place.

583
00:28:33,070 --> 00:28:35,650
Now, it can work through
the central place,

584
00:28:35,650 --> 00:28:39,600
but I'm talking
about, yeah, a bus

585
00:28:39,600 --> 00:28:43,280
is detected for a
particular light,

586
00:28:43,280 --> 00:28:46,590
hold that particular
light green for me.

587
00:28:46,590 --> 00:28:50,450
It doesn't do anything to
any other intersection.

588
00:28:50,450 --> 00:28:52,346
AUDIENCE: But I meant
does it send a signal

589
00:28:52,346 --> 00:28:54,470
to some central control
which then tells that light

590
00:28:54,470 --> 00:28:57,320
to change?

591
00:28:57,320 --> 00:28:59,130
PETER FURTH: That's an option.

592
00:28:59,130 --> 00:29:03,930
So in Zurich, yes, they
do that but man you need

593
00:29:03,930 --> 00:29:05,180
all kinds of cabling for that.

594
00:29:05,180 --> 00:29:11,420
In Zurich the controllers on
the street are 100% slaves.

595
00:29:11,420 --> 00:29:13,910
All they do is, when
the central computer

596
00:29:13,910 --> 00:29:16,850
tells them to change from green
to yellow they just say, yes.

597
00:29:16,850 --> 00:29:19,220
And the only other software
they have running in them

598
00:29:19,220 --> 00:29:23,630
is some kind of checking to
make sure that they're not

599
00:29:23,630 --> 00:29:24,590
violating something.

600
00:29:24,590 --> 00:29:29,760
But that's a very unusual
setup that was done ages ago.

601
00:29:29,760 --> 00:29:32,690
Nowadays we have very
reliable microcomputers

602
00:29:32,690 --> 00:29:34,130
in the controllers.

603
00:29:34,130 --> 00:29:37,070
So the central
computer will make

604
00:29:37,070 --> 00:29:40,940
sure every intersection
is on the clock,

605
00:29:40,940 --> 00:29:43,730
every intersection is supposed
to have its certain offset--

606
00:29:43,730 --> 00:29:47,310
you turn green at a
certain time in the cycle.

607
00:29:47,310 --> 00:29:49,980
And it will give them
the basic parameters--

608
00:29:49,980 --> 00:29:53,690
30 seconds for this street,
20 seconds for this phase,

609
00:29:53,690 --> 00:29:55,790
20 seconds for this
phase, and so on.

610
00:29:55,790 --> 00:29:57,650
And it will say,
and you're allowed

611
00:29:57,650 --> 00:30:00,530
to give a 15 second
green extension.

612
00:30:00,530 --> 00:30:02,840
And then it's the
local controller

613
00:30:02,840 --> 00:30:05,900
that will actually do it.

614
00:30:05,900 --> 00:30:06,639
Yeah.

615
00:30:06,639 --> 00:30:12,280
AUDIENCE: [INAUDIBLE] means
that the detector is right there

616
00:30:12,280 --> 00:30:13,940
at the intersection?

617
00:30:13,940 --> 00:30:16,190
PETER FURTH: Well it means
that the stop is just

618
00:30:16,190 --> 00:30:17,240
before the intersection.

619
00:30:17,240 --> 00:30:18,720
AUDIENCE: OK.

620
00:30:18,720 --> 00:30:21,110
PETER FURTH: So if
I put my detector--

621
00:30:21,110 --> 00:30:24,380
normally, let's say I want to
give a 15 second extension,

622
00:30:24,380 --> 00:30:28,910
I locate my detector 15 seconds
upstream of the traffic light.

623
00:30:28,910 --> 00:30:31,760
Well, what's 15
seconds ahead when

624
00:30:31,760 --> 00:30:34,420
there is a dwell time in there?

625
00:30:34,420 --> 00:30:39,840
So you know how random
dwell times are, right?

626
00:30:39,840 --> 00:30:43,409
Are there going to be one,
two, five people getting off?

627
00:30:43,409 --> 00:30:44,700
How many people are getting on?

628
00:30:44,700 --> 00:30:48,270
Maybe somebody who needs
assistance or having

629
00:30:48,270 --> 00:30:51,140
trouble with their fares.

630
00:30:51,140 --> 00:30:55,884
So because of that we won't
usually call for an extension

631
00:30:55,884 --> 00:30:57,800
if there is a stop in
between because we don't

632
00:30:57,800 --> 00:30:59,091
know how long it's going to be.

633
00:30:59,091 --> 00:31:07,230
So near side stops, not entirely
but they get some benefit.

634
00:31:07,230 --> 00:31:10,670
If the bus is pulling out
two seconds of extension,

635
00:31:10,670 --> 00:31:13,860
that's nice but it's
only two seconds.

636
00:31:13,860 --> 00:31:16,200
So it nearly kills
the effectiveness

637
00:31:16,200 --> 00:31:17,940
of green extension.

638
00:31:17,940 --> 00:31:21,864
So that's a reason if you
want to do transit priority,

639
00:31:21,864 --> 00:31:23,280
you review your
route and you say,

640
00:31:23,280 --> 00:31:26,830
can I move the stops
to the far side.

641
00:31:26,830 --> 00:31:29,980
There are a lot of other reasons
to move stops to the far side.

642
00:31:29,980 --> 00:31:33,250
Transit agencies around
the country where they can

643
00:31:33,250 --> 00:31:34,840
are moving stops
to the far side.

644
00:31:34,840 --> 00:31:36,970
So in the NBTA recently
they did a review

645
00:31:36,970 --> 00:31:38,260
of all their key routes.

646
00:31:38,260 --> 00:31:41,650
And one thing they looked at
is, can we relocate stops?

647
00:31:41,650 --> 00:31:43,690
But they have criteria--

648
00:31:43,690 --> 00:31:47,230
where there's a stop there has
to be a level landing place.

649
00:31:47,230 --> 00:31:50,500
There can't be fire hydrants
and telephone poles in the way.

650
00:31:50,500 --> 00:31:53,440
There can't be driveways.

651
00:31:53,440 --> 00:31:57,430
So some of the streets that
I've looked at for, could we

652
00:31:57,430 --> 00:32:01,090
do transit priority, and first
thing I would say, oh no, it's

653
00:32:01,090 --> 00:32:02,170
a near side stop.

654
00:32:02,170 --> 00:32:04,582
We've got to move it to the
other side of the street.

655
00:32:04,582 --> 00:32:06,040
But on the other
side of the street

656
00:32:06,040 --> 00:32:07,840
there's a driveway
every 30 feet,

657
00:32:07,840 --> 00:32:10,210
you can't put a bus stop there.

658
00:32:10,210 --> 00:32:13,550
Or there's a firehouse, you
can't put a bus stop there.

659
00:32:13,550 --> 00:32:16,870
So sometimes we're stuck
with near side stops.

660
00:32:16,870 --> 00:32:18,926
And then green
extension just ain't

661
00:32:18,926 --> 00:32:20,050
going to help us very much.

662
00:32:25,250 --> 00:32:25,750
OK.

663
00:32:25,750 --> 00:32:33,720
Before I go into
more tactics, let

664
00:32:33,720 --> 00:32:37,080
me go through this list
of common weaknesses

665
00:32:37,080 --> 00:32:38,680
in trying to do it.

666
00:32:38,680 --> 00:32:42,540
So one weakness that I've
seen a lot here in the US

667
00:32:42,540 --> 00:32:45,270
is what I call
cautious priority.

668
00:32:45,270 --> 00:32:49,240
So all this equipment they
put in this transit priority

669
00:32:49,240 --> 00:32:49,740
system.

670
00:32:49,740 --> 00:32:52,110
But the traffic engineers
are so afraid it's

671
00:32:52,110 --> 00:32:54,930
going to screw up
traffic that they'll say,

672
00:32:54,930 --> 00:32:56,760
once we give
priority to a bus we

673
00:32:56,760 --> 00:32:58,710
inhibit the whole
system for five minutes

674
00:32:58,710 --> 00:33:01,050
to give the signal
a chance to recover

675
00:33:01,050 --> 00:33:03,840
or we inhibit at least
for another cycle.

676
00:33:06,820 --> 00:33:12,370
Or if the traffic level on
the cross street is too much,

677
00:33:12,370 --> 00:33:15,870
just turn off the
signal priorities.

678
00:33:15,870 --> 00:33:16,370
OK.

679
00:33:16,370 --> 00:33:20,510
So the Silver Line running
on Washington Street

680
00:33:20,510 --> 00:33:22,190
has a priority system.

681
00:33:26,310 --> 00:33:29,040
Some of the cross streets
have so much traffic

682
00:33:29,040 --> 00:33:31,950
that they have this rule--
if the cross street volume is

683
00:33:31,950 --> 00:33:32,940
too much, turn it off.

684
00:33:32,940 --> 00:33:34,140
Well it's turned off, OK.

685
00:33:34,140 --> 00:33:36,420
So the bus never gets
priority at Melnea Cass,

686
00:33:36,420 --> 00:33:39,660
it never gets
priority at Mass Ave.

687
00:33:39,660 --> 00:33:42,630
Many of the cross streets
bus has the green light

688
00:33:42,630 --> 00:33:45,180
for like 70 out of 90
seconds in the cycle.

689
00:33:45,180 --> 00:33:47,280
So it's almost always
green so the bus almost

690
00:33:47,280 --> 00:33:48,370
never needs priority.

691
00:33:48,370 --> 00:33:53,460
So there is priority, but
the benefit is very time.

692
00:33:53,460 --> 00:33:56,002
So in the end, what do you get?

693
00:33:56,002 --> 00:33:56,960
You get almost nothing.

694
00:34:00,140 --> 00:34:04,880
And then a second
weakness is not

695
00:34:04,880 --> 00:34:07,910
thinking about the impact
of priority on traffic

696
00:34:07,910 --> 00:34:09,889
and then unnecessarily
hurting traffic,

697
00:34:09,889 --> 00:34:13,669
like not having a check-out
detector that I mentioned.

698
00:34:13,669 --> 00:34:16,880
But the second
bullet there, that's

699
00:34:16,880 --> 00:34:21,840
an important one I want you to
think about, is compensation.

700
00:34:21,840 --> 00:34:26,130
Compensation is a key
to making priority not

701
00:34:26,130 --> 00:34:28,020
hurt traffic so bad.

702
00:34:28,020 --> 00:34:29,670
And by compensation
what do I mean?

703
00:34:29,670 --> 00:34:33,239
What I mean is if I'm going to
give the bus street 15 seconds,

704
00:34:33,239 --> 00:34:36,420
I'm taking those 15
seconds away from somebody.

705
00:34:36,420 --> 00:34:39,510
Are you going to give it back?

706
00:34:39,510 --> 00:34:41,834
The language that
traffic engineers use

707
00:34:41,834 --> 00:34:43,060
is they use the word borrow.

708
00:34:43,060 --> 00:34:47,139
They say, oh, we'll just borrow
15 seconds from phase two.

709
00:34:47,139 --> 00:34:49,630
And then I ask are you
going to give it back?

710
00:34:49,630 --> 00:34:50,909
And they say, well, no.

711
00:34:50,909 --> 00:34:55,690
I say, well, then it's not
borrowing, that's stealing.

712
00:34:55,690 --> 00:34:59,560
So if you take away 15
seconds from phase two,

713
00:34:59,560 --> 00:35:07,480
and phase two now they
can't clear its queue.

714
00:35:07,480 --> 00:35:09,640
So now it's going to
have a long queue.

715
00:35:09,640 --> 00:35:12,550
And then the traffic
engineers will say, oh no,

716
00:35:12,550 --> 00:35:16,570
now if we let them have priority
in the next cycle as well,

717
00:35:16,570 --> 00:35:19,210
oh no, what a disaster.

718
00:35:19,210 --> 00:35:20,750
So that's why you
get these rules,

719
00:35:20,750 --> 00:35:23,620
like if we do priority, no
priority for the next cycle

720
00:35:23,620 --> 00:35:26,660
or the next five minutes.

721
00:35:26,660 --> 00:35:32,380
But if I hold the light green
for let's say East Street

722
00:35:32,380 --> 00:35:35,470
for the bus, so I hold
the light green 15 seconds

723
00:35:35,470 --> 00:35:39,110
for East Street, who's
going to get through

724
00:35:39,110 --> 00:35:40,510
in addition to the bus?

725
00:35:40,510 --> 00:35:42,370
A bunch of cars, right?

726
00:35:42,370 --> 00:35:45,880
A bunch of cars who otherwise
would have been in the queue

727
00:35:45,880 --> 00:35:47,524
for the next cycle.

728
00:35:47,524 --> 00:35:49,690
So that means when we come
around to the next cycle,

729
00:35:49,690 --> 00:35:51,400
East Street is not
going to need as much

730
00:35:51,400 --> 00:35:55,690
green because some of their
cars already got through.

731
00:35:55,690 --> 00:35:57,810
Meanwhile, other streets
whose green we took they

732
00:35:57,810 --> 00:35:58,800
need more green.

733
00:35:58,800 --> 00:36:03,810
So hey, why not just be
reasonable and fair about it.

734
00:36:03,810 --> 00:36:07,004
Since we gave East Street some
extra green, in the next cycle

735
00:36:07,004 --> 00:36:08,670
we'll give the other
streets extra green

736
00:36:08,670 --> 00:36:10,860
and we'll take some
away from East Street.

737
00:36:10,860 --> 00:36:12,690
That's compensation.

738
00:36:12,690 --> 00:36:14,820
That's a sensible
way of doing things.

739
00:36:14,820 --> 00:36:18,570
And what you'll see
is we don't do that.

740
00:36:18,570 --> 00:36:23,640
We can't do that with much of
the standard way of controlling

741
00:36:23,640 --> 00:36:26,730
lights that we follow
here in the US.

742
00:36:26,730 --> 00:36:29,490
And that's the
inflexibility that I'll

743
00:36:29,490 --> 00:36:33,170
be explaining later on.

744
00:36:33,170 --> 00:36:36,770
Then another weakness is
we'll do the easy things.

745
00:36:36,770 --> 00:36:38,030
Green extension is easy.

746
00:36:38,030 --> 00:36:40,100
So we just do green extension.

747
00:36:40,100 --> 00:36:42,920
And then, like I said, if
you have near side stops,

748
00:36:42,920 --> 00:36:44,570
well you don't get any benefit.

749
00:36:44,570 --> 00:36:46,790
And there are other tactics
that are harder to do,

750
00:36:46,790 --> 00:36:48,890
but we only do the easy ones.

751
00:36:48,890 --> 00:36:52,860
And then the last weakness
is failing to collect data.

752
00:36:52,860 --> 00:36:54,740
In something like this,
it's hard to get it

753
00:36:54,740 --> 00:36:55,650
right the first time.

754
00:36:55,650 --> 00:36:58,280
You need to do it, collect data.

755
00:36:58,280 --> 00:37:00,950
See, are my buses getting the
priority they're supposed to?

756
00:37:00,950 --> 00:37:03,860
If they're not, make some fixes.

757
00:37:03,860 --> 00:37:06,080
Is car traffic doing all right?

758
00:37:06,080 --> 00:37:09,140
Are there places where huge
queues are building up?

759
00:37:09,140 --> 00:37:10,970
And try to fix it.

760
00:37:10,970 --> 00:37:14,000
So take the objective seriously.

761
00:37:14,000 --> 00:37:19,250
So now I need to move
away from transit priority

762
00:37:19,250 --> 00:37:21,500
and just tell you something
about traffic signal

763
00:37:21,500 --> 00:37:24,440
control in general
because it's something

764
00:37:24,440 --> 00:37:27,440
that isn't covered in a lot
of the standard transportation

765
00:37:27,440 --> 00:37:29,190
planning curriculum.

766
00:37:29,190 --> 00:37:33,350
So there are two basic
paradigms for signal control.

767
00:37:33,350 --> 00:37:37,250
One is fully actuated and
the other is coordinated.

768
00:37:37,250 --> 00:37:43,400
So fully actuated
that's uncoordinated.

769
00:37:43,400 --> 00:37:46,700
With fully actuated that
means every approach

770
00:37:46,700 --> 00:37:47,960
I've got detectors.

771
00:37:47,960 --> 00:37:50,480
And the standard
detector it's a loop

772
00:37:50,480 --> 00:37:52,400
of copper in the
street, a couple

773
00:37:52,400 --> 00:37:54,500
rounds that goes to a box.

774
00:37:54,500 --> 00:37:57,770
And through the miracles
of electromagnetism

775
00:37:57,770 --> 00:38:01,940
if a vehicle drives over
it, it induces a voltage.

776
00:38:01,940 --> 00:38:03,470
And you can pick
up that voltage,

777
00:38:03,470 --> 00:38:05,300
and so you know
there's a car there.

778
00:38:05,300 --> 00:38:05,800
Yeah.

779
00:38:05,800 --> 00:38:08,220
AUDIENCE: [INAUDIBLE]

780
00:38:08,220 --> 00:38:10,440
PETER FURTH: So
there is a setting

781
00:38:10,440 --> 00:38:16,260
of how much of a voltage
change is enough because it

782
00:38:16,260 --> 00:38:17,240
has to become digital.

783
00:38:17,240 --> 00:38:19,750
It's either 0 or 1.

784
00:38:19,750 --> 00:38:22,050
So if we increase
the sensitivity,

785
00:38:22,050 --> 00:38:23,730
then it'll detect a bike.

786
00:38:23,730 --> 00:38:25,890
But then the danger
is it will also detect

787
00:38:25,890 --> 00:38:28,810
a car in the next lane over.

788
00:38:28,810 --> 00:38:30,460
So there is a trade off there.

789
00:38:30,460 --> 00:38:34,900
So then if we want
to detect bikes,

790
00:38:34,900 --> 00:38:37,570
we use a figure 8 configuration.

791
00:38:37,570 --> 00:38:42,010
And then we try to educate the
bicyclists, drive right down

792
00:38:42,010 --> 00:38:43,750
the middle of that figure 8.

793
00:38:43,750 --> 00:38:47,450
And that's where you'll
get picked up the most.

794
00:38:47,450 --> 00:38:49,175
Hardly anybody
knows that though.

795
00:38:52,900 --> 00:38:55,620
There's another solution
to bike detection, which

796
00:38:55,620 --> 00:39:02,860
is if you're a bicyclist
like me, I like green.

797
00:39:02,860 --> 00:39:04,250
I like red.

798
00:39:04,250 --> 00:39:05,020
I like yellow.

799
00:39:05,020 --> 00:39:06,400
I like all colors.

800
00:39:06,400 --> 00:39:06,960
I just go.

801
00:39:15,081 --> 00:39:15,580
All right.

802
00:39:15,580 --> 00:39:19,130
So with fully actuated
control I've got detectors.

803
00:39:19,130 --> 00:39:21,440
And based on those
detectors, I will

804
00:39:21,440 --> 00:39:24,560
know how many seconds
has it been since a car

805
00:39:24,560 --> 00:39:27,730
passed through and
[AUDIO OUT] gap.

806
00:39:27,730 --> 00:39:30,060
And once the gap reaches
a certain threshold,

807
00:39:30,060 --> 00:39:34,410
2 and 1/2 seconds, 3 seconds,
then you have gapped out.

808
00:39:34,410 --> 00:39:36,660
Boom, your turn is over.

809
00:39:36,660 --> 00:39:39,420
And it's the next one's turn.

810
00:39:39,420 --> 00:39:41,430
So there's no
fixed cycle length.

811
00:39:41,430 --> 00:39:42,000
Who knows?

812
00:39:42,000 --> 00:39:45,270
If traffic volume is light, we
serve you, we serve the next,

813
00:39:45,270 --> 00:39:47,280
we serve the next,
and now we're back.

814
00:39:47,280 --> 00:39:48,330
Traffic is heavy.

815
00:39:48,330 --> 00:39:51,460
It might take 90
seconds to cycle around.

816
00:39:51,460 --> 00:39:54,600
But it's completely
flexible like that.

817
00:39:54,600 --> 00:39:59,640
And if I interrupt something
like that for transit

818
00:39:59,640 --> 00:40:03,790
priority and now
there's a longer queue--

819
00:40:03,790 --> 00:40:06,790
OK, everybody's been waiting
an extra 15 seconds because

820
00:40:06,790 --> 00:40:09,160
of this transit priority.

821
00:40:09,160 --> 00:40:13,570
Well, when their turn comes
up if they've got more cars,

822
00:40:13,570 --> 00:40:16,300
well the detector will say,
hey, they still have cars,

823
00:40:16,300 --> 00:40:17,590
still have cars, yeah.

824
00:40:17,590 --> 00:40:19,280
So keep them going,
keep them going.

825
00:40:19,280 --> 00:40:19,780
OK.

826
00:40:19,780 --> 00:40:22,850
Now we finally have a gap
you're over, onto the next one.

827
00:40:22,850 --> 00:40:26,110
And if East Street
like I was saying

828
00:40:26,110 --> 00:40:30,340
has less traffic, the street
that the bus was on because it

829
00:40:30,340 --> 00:40:34,890
got that green extension,
when its turn comes up instead

830
00:40:34,890 --> 00:40:37,680
of holding the
light for 35 seconds

831
00:40:37,680 --> 00:40:40,290
like it usually does it'll
hold the light for 25 seconds

832
00:40:40,290 --> 00:40:42,070
and then say, I'm all done.

833
00:40:42,070 --> 00:40:43,510
No more traffic.

834
00:40:43,510 --> 00:40:50,970
So fully actuated control is a
great background for priority

835
00:40:50,970 --> 00:40:55,710
because it's inherently
flexible, it's cycle free,

836
00:40:55,710 --> 00:40:59,660
it has that built
in compensation.

837
00:40:59,660 --> 00:41:03,980
But then there's another
way of doing control,

838
00:41:03,980 --> 00:41:06,380
another basic
paradigm for control,

839
00:41:06,380 --> 00:41:09,590
which is coordinated control.

840
00:41:09,590 --> 00:41:13,910
In the US, I'm
showing the most kind

841
00:41:13,910 --> 00:41:16,940
of the basic paradigm, which
is the dual ring with eight

842
00:41:16,940 --> 00:41:17,986
phases.

843
00:41:17,986 --> 00:41:20,360
I'm not including right turns
because right turns usually

844
00:41:20,360 --> 00:41:21,710
don't have their own lights.

845
00:41:21,710 --> 00:41:25,100
The right turns just go
with the through movements.

846
00:41:25,100 --> 00:41:27,320
And with coordinated
control like this

847
00:41:27,320 --> 00:41:34,460
we have EBL, that means
eastbound left, westbound

848
00:41:34,460 --> 00:41:37,370
through, WBT, westbound through.

849
00:41:37,370 --> 00:41:40,380
So the east-west
street has its time.

850
00:41:40,380 --> 00:41:42,740
There's an upper ring
and a lower ring.

851
00:41:42,740 --> 00:41:44,990
And the rings that
are in parallel they

852
00:41:44,990 --> 00:41:46,110
can move together.

853
00:41:46,110 --> 00:41:48,590
So when the light starts
green, eastbound left

854
00:41:48,590 --> 00:41:51,800
and westbound left, one and
five, they're green together.

855
00:41:51,800 --> 00:41:53,900
What comes next, two or six?

856
00:41:53,900 --> 00:41:55,220
That depends.

857
00:41:55,220 --> 00:41:57,980
Whichever one has more
traffic, one or five,

858
00:41:57,980 --> 00:42:02,510
that will stay green
because it has detectors

859
00:42:02,510 --> 00:42:04,280
while the other one gaps out.

860
00:42:04,280 --> 00:42:07,430
So maybe five gaps out first
because it had less traffic.

861
00:42:07,430 --> 00:42:10,220
Then six becomes
green along with one.

862
00:42:10,220 --> 00:42:14,090
Eventually one gaps out, and
now six is green along with two.

863
00:42:14,090 --> 00:42:16,620
But then six and two
have to end together.

864
00:42:16,620 --> 00:42:20,150
And then we have the same thing
for the north-south street.

865
00:42:20,150 --> 00:42:24,530
So this could be fully
actuated, but when

866
00:42:24,530 --> 00:42:26,240
I say it's coordinated
what I mean

867
00:42:26,240 --> 00:42:30,840
is phases two and six those
are the coordinated phases.

868
00:42:30,840 --> 00:42:35,310
And the cycle goes from
the end of two and six

869
00:42:35,310 --> 00:42:37,380
until the next end
of two and six.

870
00:42:37,380 --> 00:42:39,180
And that is a fixed
amount of time.

871
00:42:39,180 --> 00:42:41,550
So if it's 110
second cycle, it's

872
00:42:41,550 --> 00:42:44,790
always 110 seconds
from this point

873
00:42:44,790 --> 00:42:48,960
until when it
comes around again.

874
00:42:48,960 --> 00:42:51,132
These phases can
have some actuation.

875
00:42:51,132 --> 00:42:52,340
They can have some detectors.

876
00:42:52,340 --> 00:42:55,430
And so they might run
shorter than scheduled.

877
00:42:55,430 --> 00:42:58,160
And if they gap out
quicker, run short,

878
00:42:58,160 --> 00:43:01,640
and this one gaps out, it
runs short, this one gaps out,

879
00:43:01,640 --> 00:43:05,360
it runs short that means two and
six are going to start early.

880
00:43:05,360 --> 00:43:07,550
But if they start early,
they never end early.

881
00:43:07,550 --> 00:43:09,590
They run their full
length because that's

882
00:43:09,590 --> 00:43:12,140
how we have the full cycle.

883
00:43:12,140 --> 00:43:14,390
And the advantage
to do that is when

884
00:43:14,390 --> 00:43:18,410
you have many signals
in a line on an arterial

885
00:43:18,410 --> 00:43:20,870
and you want a green
wave, you have them

886
00:43:20,870 --> 00:43:22,370
all on the same cycle.

887
00:43:22,370 --> 00:43:24,870
And then you have their
different offsets.

888
00:43:24,870 --> 00:43:29,330
So let's say signal 1 it's
green starts at time 0.

889
00:43:29,330 --> 00:43:33,050
The next one that's maybe 20
seconds away, well it's green

890
00:43:33,050 --> 00:43:34,440
starts at time 20.

891
00:43:34,440 --> 00:43:36,590
And that way the cars
can get a green wave.

892
00:43:36,590 --> 00:43:37,760
That's the idea.

893
00:43:37,760 --> 00:43:38,260
Yeah.

894
00:43:38,260 --> 00:43:41,620
AUDIENCE: Are these doing that
while left turns [INAUDIBLE]??

895
00:43:41,620 --> 00:43:42,370
PETER FURTH: Yeah.

896
00:43:42,370 --> 00:43:44,930
As I drew it here, it's
protected left turns.

897
00:43:44,930 --> 00:43:46,650
You can have protected
plus permitted.

898
00:43:46,650 --> 00:43:48,624
I mean there are variations.

899
00:43:48,624 --> 00:43:51,290
If there might be no left turns,
then you can just take them out

900
00:43:51,290 --> 00:43:54,390
but that's the basic scheme.

901
00:43:54,390 --> 00:43:58,250
Now, what I want you to
think about is suppose

902
00:43:58,250 --> 00:44:03,580
the bus is on phase two
which is a common case.

903
00:44:03,580 --> 00:44:07,750
That's your Main Street the
street that's coordinated.

904
00:44:07,750 --> 00:44:10,500
And the bus says, I
need an extension.

905
00:44:10,500 --> 00:44:11,231
Extend the green.

906
00:44:11,231 --> 00:44:11,730
All right.

907
00:44:11,730 --> 00:44:16,680
We're going to borrow some
time from the later phases.

908
00:44:16,680 --> 00:44:19,692
So we're going to hold the
light green an extra 15 seconds.

909
00:44:22,650 --> 00:44:27,660
But remember we are
guaranteeing that at the end

910
00:44:27,660 --> 00:44:28,950
we've got to be on time again.

911
00:44:28,950 --> 00:44:34,730
So now we've only got 85 seconds
left to complete the cycle.

912
00:44:34,730 --> 00:44:37,790
And phase two and
six, they are not only

913
00:44:37,790 --> 00:44:39,350
guaranteed their
ending time, they're

914
00:44:39,350 --> 00:44:41,270
also guaranteed
they're starting time.

915
00:44:41,270 --> 00:44:45,282
So that means we have to take
those 15 seconds out of 3, 7,

916
00:44:45,282 --> 00:44:47,850
4, 8, and 1, 5.

917
00:44:47,850 --> 00:44:52,020
So to make things simple let's
only look at the bottom ring.

918
00:44:52,020 --> 00:44:56,400
So I have to take 15 seconds.

919
00:44:56,400 --> 00:44:58,770
The first generation, they
would take the whole 15

920
00:44:58,770 --> 00:45:01,080
seconds out of phase
seven and then phase seven

921
00:45:01,080 --> 00:45:01,950
would get canceled.

922
00:45:01,950 --> 00:45:03,220
Well that caused big problems.

923
00:45:03,220 --> 00:45:05,490
So now what they'll do
is they'll proportionally

924
00:45:05,490 --> 00:45:06,120
take it out.

925
00:45:06,120 --> 00:45:11,070
So let's say phase
seven is normally

926
00:45:11,070 --> 00:45:13,450
scheduled to have 20 seconds,
and this one is normally

927
00:45:13,450 --> 00:45:16,410
scheduled at 30 seconds,
and this one is normally

928
00:45:16,410 --> 00:45:18,130
scheduled to have 20 seconds.

929
00:45:18,130 --> 00:45:22,530
So 20, 30, 20,
that's sums up to 70.

930
00:45:22,530 --> 00:45:24,960
So I'm taking 15 seconds out.

931
00:45:24,960 --> 00:45:27,940
So a portion of that I'd take
from you, I'd take from you,

932
00:45:27,940 --> 00:45:29,370
I'd take from you.

933
00:45:29,370 --> 00:45:31,750
You get the idea.

934
00:45:31,750 --> 00:45:34,030
Is there any compensation
going on here?

935
00:45:34,030 --> 00:45:36,580
None at all.

936
00:45:36,580 --> 00:45:43,170
Phase six, the coordinated
phase, got an extra 15 seconds.

937
00:45:43,170 --> 00:45:47,920
But the competing phases,
they all got cut short.

938
00:45:47,920 --> 00:45:53,000
And now phase six comes
up for a full phase.

939
00:45:53,000 --> 00:45:57,501
That's the way our coordinated
systems are programmed to work.

940
00:45:57,501 --> 00:45:59,250
They don't have to be
programmed that way,

941
00:45:59,250 --> 00:46:00,560
but that's the way they are.

942
00:46:00,560 --> 00:46:03,740
If you buy them from
any American supplier,

943
00:46:03,740 --> 00:46:07,450
that's how they're
programmed to work.

944
00:46:07,450 --> 00:46:10,570
So when you say let's
add transit priority

945
00:46:10,570 --> 00:46:12,430
on top of that, now
you can understand

946
00:46:12,430 --> 00:46:14,440
why the traffic engineers
say, I don't know

947
00:46:14,440 --> 00:46:16,900
about a 30 second extension.

948
00:46:16,900 --> 00:46:19,630
Or oh, after giving
priority in one cycle

949
00:46:19,630 --> 00:46:21,760
we better not give
priority in the next.

950
00:46:21,760 --> 00:46:24,880
Because it can really
screw up traffic.

951
00:46:24,880 --> 00:46:28,560
It lacks this mechanism
for compensation.

952
00:46:28,560 --> 00:46:30,120
And compensating would be easy.

953
00:46:30,120 --> 00:46:36,110
It would be say, let seven run
for its full scheduled time

954
00:46:36,110 --> 00:46:37,230
unless it gaps out.

955
00:46:37,230 --> 00:46:39,610
I mean if it gaps out if
there's no traffic, don't.

956
00:46:39,610 --> 00:46:43,140
And allow six to
start late because six

957
00:46:43,140 --> 00:46:44,220
got some extra time.

958
00:46:44,220 --> 00:46:47,940
It probably doesn't
need its full amount.

959
00:46:47,940 --> 00:46:49,754
But we don't do that.

960
00:46:52,580 --> 00:46:56,150
And then if we do
a longer extension,

961
00:46:56,150 --> 00:46:58,340
we get out of coordination,
we have to return back,

962
00:46:58,340 --> 00:46:59,570
and I won't go into that.

963
00:47:03,925 --> 00:47:05,800
I'll talk about a second
tactic, and then I'm

964
00:47:05,800 --> 00:47:10,240
going to take a break so you
can hear about how they've done

965
00:47:10,240 --> 00:47:12,130
priority in the Netherlands.

966
00:47:12,130 --> 00:47:16,210
A second tactic is
Early Green, OK?

967
00:47:16,210 --> 00:47:21,250
So in this diagram,
the phase that's green,

968
00:47:21,250 --> 00:47:24,540
that's the phase in which
the bus is coming, OK?

969
00:47:24,540 --> 00:47:26,250
And the phases that
precede it, those

970
00:47:26,250 --> 00:47:29,280
are competing phases, the
cross street or left turns

971
00:47:29,280 --> 00:47:31,380
that are waiting, OK?

972
00:47:31,380 --> 00:47:36,496
And the red dash line,
that's when in the cycle

973
00:47:36,496 --> 00:47:37,620
the bus is going to arrive.

974
00:47:37,620 --> 00:47:41,280
So I've got a
situation where the bus

975
00:47:41,280 --> 00:47:44,070
is expected to arrive near
the beginning of the left turn

976
00:47:44,070 --> 00:47:45,184
phase.

977
00:47:45,184 --> 00:47:47,100
And then it would have
to wait through the end

978
00:47:47,100 --> 00:47:48,480
of the left turn phase.

979
00:47:48,480 --> 00:47:52,140
And finally its
phase would be green.

980
00:47:52,140 --> 00:48:01,450
So with early green, I could
shorten the left turn phase.

981
00:48:01,450 --> 00:48:06,040
I could even shorten the
north-south phase before it.

982
00:48:06,040 --> 00:48:09,850
So that now it's a shorter wait
until the bus's green comes up.

983
00:48:09,850 --> 00:48:11,710
Maybe I even skip the left turn.

984
00:48:11,710 --> 00:48:14,530
I shorten the through,
phase skip the left turn

985
00:48:14,530 --> 00:48:19,990
and really make things
better for the bus that way.

986
00:48:19,990 --> 00:48:22,630
So an interesting way
to look at early green

987
00:48:22,630 --> 00:48:24,830
compared to green extension.

988
00:48:24,830 --> 00:48:29,410
It's a small benefit because
if I make the green start

989
00:48:29,410 --> 00:48:32,230
10 seconds early, that will
reduce the delay for the bus

990
00:48:32,230 --> 00:48:33,550
by 10 seconds.

991
00:48:36,120 --> 00:48:39,120
Remember with green
extension, 10 second extension

992
00:48:39,120 --> 00:48:41,430
could save a bus 90 seconds.

993
00:48:41,430 --> 00:48:46,950
But this-- it's a small
benefit, but who benefits?

994
00:48:46,950 --> 00:48:48,530
Any bus arriving on red.

995
00:48:48,530 --> 00:48:53,240
And red is usually a long time,
and a large percentage of buses

996
00:48:53,240 --> 00:48:54,230
arrive on red.

997
00:48:54,230 --> 00:48:58,070
Actually, the early part of
green, buses can also benefit.

998
00:48:58,070 --> 00:49:02,030
So it's a small benefit to
a large number of buses.

999
00:49:02,030 --> 00:49:02,530
Yeah.

1000
00:49:02,530 --> 00:49:04,488
AUDIENCE: For skip you
have the question marks.

1001
00:49:04,488 --> 00:49:07,280
Why wouldn't you just flip the
two cycles, flip the left--

1002
00:49:07,280 --> 00:49:08,930
PETER FURTH: Well
that's a great idea.

1003
00:49:08,930 --> 00:49:11,040
Flipping them,
but now then you'd

1004
00:49:11,040 --> 00:49:13,070
have to give that
tactic a different name.

1005
00:49:13,070 --> 00:49:16,900
And that name is
called phase rotation.

1006
00:49:16,900 --> 00:49:17,830
So yeah.

1007
00:49:17,830 --> 00:49:22,330
And some people think phase
rotation is an invitation

1008
00:49:22,330 --> 00:49:23,990
to traffic Armageddon.

1009
00:49:23,990 --> 00:49:25,090
It's going to be disaster.

1010
00:49:25,090 --> 00:49:27,160
Cars are going to be
smashing into each other

1011
00:49:27,160 --> 00:49:30,220
because people
expect their phase

1012
00:49:30,220 --> 00:49:31,450
to come up at a certain time.

1013
00:49:31,450 --> 00:49:33,580
And if it doesn't, they're going
to think the light is broken

1014
00:49:33,580 --> 00:49:34,463
and go through.

1015
00:49:37,850 --> 00:49:39,885
This is something
that can be tested.

1016
00:49:39,885 --> 00:49:40,510
AUDIENCE: Yeah.

1017
00:49:40,510 --> 00:49:41,840
I was just going to
ask whether or not--

1018
00:49:41,840 --> 00:49:43,784
I think I've been at
a light before where

1019
00:49:43,784 --> 00:49:46,350
I had a skipped left turn
and I was pretty pissed off.

1020
00:49:46,350 --> 00:49:48,294
I was just curious
how that goes down.

1021
00:49:48,294 --> 00:49:51,830
How many people does it--

1022
00:49:51,830 --> 00:49:55,820
PETER FURTH: So in Zurich when
the traffic signal programmers

1023
00:49:55,820 --> 00:49:59,490
said, we can give better
priority if we can do this.

1024
00:49:59,490 --> 00:50:02,619
The higher ups were
worried about so they

1025
00:50:02,619 --> 00:50:04,160
said, what we're
going to do is we're

1026
00:50:04,160 --> 00:50:06,410
going to have a campaign
in which we're going to let

1027
00:50:06,410 --> 00:50:09,140
the people in the city know
that for the next six months

1028
00:50:09,140 --> 00:50:11,240
the sequence of
traffic signals is

1029
00:50:11,240 --> 00:50:13,700
going to be completely random.

1030
00:50:13,700 --> 00:50:17,830
Just wait until
your green comes up.

1031
00:50:17,830 --> 00:50:19,480
And they did that.

1032
00:50:19,480 --> 00:50:24,935
And then they went to
having a phase rotation.

1033
00:50:27,980 --> 00:50:30,080
AUDIENCE: Isn't it the
law that you're supposed

1034
00:50:30,080 --> 00:50:31,710
to wait until the green light?

1035
00:50:31,710 --> 00:50:33,470
And they're assuming people--

1036
00:50:33,470 --> 00:50:34,480
PETER FURTH: Yeah.

1037
00:50:34,480 --> 00:50:37,920
So in my life-- and my life is
a little longer than yours, so

1038
00:50:37,920 --> 00:50:42,360
in my lifetime of being
out on the streets

1039
00:50:42,360 --> 00:50:47,090
and I do drive a car sometimes,
once I went through a red light

1040
00:50:47,090 --> 00:50:50,360
because I waited
like two whole cycles

1041
00:50:50,360 --> 00:50:51,800
and my phase never came up.

1042
00:50:51,800 --> 00:50:53,300
So I figured the
detector was broken

1043
00:50:53,300 --> 00:50:56,720
and there's no traffic around
here anyway, so I'm going.

1044
00:50:56,720 --> 00:51:00,616
So people will do
that now and then.

1045
00:51:00,616 --> 00:51:04,010
It doesn't happen often though.

1046
00:51:04,010 --> 00:51:05,810
But what you say about
won't people wait,

1047
00:51:05,810 --> 00:51:08,780
there is one class of
people who won't wait.

1048
00:51:08,780 --> 00:51:10,310
And that's called bicyclists.

1049
00:51:10,310 --> 00:51:13,160
So you got to
watch out for them.

1050
00:51:13,160 --> 00:51:14,260
Think about their safety.

1051
00:51:16,850 --> 00:51:22,590
Now, in practice, often
you can't get much benefit

1052
00:51:22,590 --> 00:51:26,530
from early green
because who's green

1053
00:51:26,530 --> 00:51:28,494
are you trying to cut short?

1054
00:51:28,494 --> 00:51:29,910
If what you're
trying to cut short

1055
00:51:29,910 --> 00:51:32,220
is the cross streets green,
the cross streets green

1056
00:51:32,220 --> 00:51:36,060
is often determined
by pedestrians.

1057
00:51:36,060 --> 00:51:38,040
And we don't cut
pedestrian phases.

1058
00:51:38,040 --> 00:51:42,100
Pedestrians and transit you
know we're on the same team.

1059
00:51:42,100 --> 00:51:45,480
We don't want to hurt one to
help the other because all

1060
00:51:45,480 --> 00:51:48,510
of our transit passengers become
pedestrians as soon as they

1061
00:51:48,510 --> 00:51:50,130
get off the bus.

1062
00:51:50,130 --> 00:51:55,230
So a lot of times you just can't
do early green because you've

1063
00:51:55,230 --> 00:51:59,400
got a wide street, the cars
need about 15 seconds of green

1064
00:51:59,400 --> 00:52:01,830
to get through, but the
pedestrians need 24 seconds.

1065
00:52:01,830 --> 00:52:04,170
So the green light's
24 seconds, it's

1066
00:52:04,170 --> 00:52:06,180
entirely because it's
what the pedestrians need.

1067
00:52:06,180 --> 00:52:09,150
You can't cut that short.

1068
00:52:09,150 --> 00:52:14,100
So that's a practical issue
that early green there

1069
00:52:14,100 --> 00:52:18,420
are limitations unless you
can detect the bus really

1070
00:52:18,420 --> 00:52:22,320
far in advance and cut
something else short.

1071
00:52:22,320 --> 00:52:36,360
So let me take a break now
and introduce Jan Nederveen.

1072
00:52:36,360 --> 00:52:42,330
Jan is a senior transportation
planner with the city of Delft.

1073
00:52:42,330 --> 00:52:48,070
And I get the privilege every
summer for the last 10 years,

1074
00:52:48,070 --> 00:52:51,240
I've been taking 20 or
25 Northeastern students

1075
00:52:51,240 --> 00:52:54,690
to Delft for five weeks
for a course in sustainable

1076
00:52:54,690 --> 00:52:56,100
transportation.

1077
00:52:56,100 --> 00:52:59,720
And there they get to enjoy
incredible bike paths,

1078
00:52:59,720 --> 00:53:05,040
incredible roundabouts,
streets rebuilt

1079
00:53:05,040 --> 00:53:08,310
to be safe for
public transportation

1080
00:53:08,310 --> 00:53:11,220
systems, new train
station, fantastic stuff.

1081
00:53:11,220 --> 00:53:13,530
And it turns out the guy who
plans a lot of this stuff

1082
00:53:13,530 --> 00:53:14,910
is sitting right here.

1083
00:53:14,910 --> 00:53:16,620
And he often speaks
to our students

1084
00:53:16,620 --> 00:53:18,790
and explains it and the
philosophy behind it.

1085
00:53:18,790 --> 00:53:23,100
So Jan, would you come and
say something about how do you

1086
00:53:23,100 --> 00:53:27,250
do transit priority in Delft.

1087
00:53:27,250 --> 00:53:28,000
JAN NEDERVEEN: OK.

1088
00:53:28,000 --> 00:53:28,499
Welcome.

1089
00:53:28,499 --> 00:53:31,010
Thank you for having me here.

1090
00:53:31,010 --> 00:53:34,270
I'm going to tell you something
that works that I don't do

1091
00:53:34,270 --> 00:53:35,710
but my colleagues do.

1092
00:53:35,710 --> 00:53:39,670
I've got three people in
my department doing traffic

1093
00:53:39,670 --> 00:53:41,200
engineering, traffic lights.

1094
00:53:41,200 --> 00:53:44,440
They design it, they build
it, and they maintain it.

1095
00:53:44,440 --> 00:53:47,500
So what I'll show you here
is part of the thoughts

1096
00:53:47,500 --> 00:53:51,400
they have done and I only
focus on public transport.

1097
00:53:51,400 --> 00:53:54,730
Peter offers many times
a lot about cycling

1098
00:53:54,730 --> 00:53:59,060
but this time it will
be public transport.

1099
00:53:59,060 --> 00:54:02,040
First I'll give you some
views about the network.

1100
00:54:02,040 --> 00:54:04,580
And then I'll show you the
two current types of priority

1101
00:54:04,580 --> 00:54:05,100
we give.

1102
00:54:05,100 --> 00:54:08,510
We do physical priority,
and we do time priority.

1103
00:54:08,510 --> 00:54:12,760
I'll show you some slides
for some examples of Delft.

1104
00:54:12,760 --> 00:54:19,710
First our city Delft,
100,000 residents close to

1105
00:54:19,710 --> 00:54:23,190
of The Hague with
600,000 residents.

1106
00:54:23,190 --> 00:54:25,470
That's how we oriented
in the busiest part,

1107
00:54:25,470 --> 00:54:28,120
dense part of the Netherlands.

1108
00:54:28,120 --> 00:54:32,950
First we had one system
to try to serve everybody.

1109
00:54:32,950 --> 00:54:36,310
And we didn't succeed in it
because our public transport

1110
00:54:36,310 --> 00:54:39,010
system was too slow.

1111
00:54:39,010 --> 00:54:41,080
And then we figured
out, oh, that's good.

1112
00:54:41,080 --> 00:54:44,500
We have two kinds of groups
we like to facilitate.

1113
00:54:44,500 --> 00:54:48,130
One group are the commuters
going to their work.

1114
00:54:48,130 --> 00:54:51,680
And what they love is
speed as soon as possible

1115
00:54:51,680 --> 00:54:53,380
going to destination.

1116
00:54:53,380 --> 00:54:57,080
In their view they only need one
stop between their front door

1117
00:54:57,080 --> 00:54:58,500
and at their destination.

1118
00:54:58,500 --> 00:55:02,280
And everything between
is not needed for them.

1119
00:55:02,280 --> 00:55:05,850
Well, I need to collect
so much more passengers

1120
00:55:05,850 --> 00:55:08,340
that we say, we
make straight lines,

1121
00:55:08,340 --> 00:55:12,750
few stops, serving high
dense volume housing

1122
00:55:12,750 --> 00:55:15,920
with high dense jobs together.

1123
00:55:15,920 --> 00:55:18,390
And then you can go for the
high speed, the high quality,

1124
00:55:18,390 --> 00:55:22,050
and we see that we
attract more passengers.

1125
00:55:22,050 --> 00:55:25,410
The second group is everybody
else-- usually elderly people,

1126
00:55:25,410 --> 00:55:27,420
people without a job.

1127
00:55:27,420 --> 00:55:31,200
And we focus on them, as
you say, they need coverage.

1128
00:55:31,200 --> 00:55:34,120
They have to go to
many local locations.

1129
00:55:34,120 --> 00:55:37,670
So we make a citywide
network covering every area.

1130
00:55:37,670 --> 00:55:40,620
And that is located
on a lower speed

1131
00:55:40,620 --> 00:55:44,400
because I have to cover
everything low frequency.

1132
00:55:44,400 --> 00:55:47,200
That's the way we
handle public transport.

1133
00:55:47,200 --> 00:55:49,110
The first group is
growing, the second group

1134
00:55:49,110 --> 00:55:51,840
is stable If you
look at the data.

1135
00:55:54,700 --> 00:55:57,230
This is how our network works.

1136
00:55:57,230 --> 00:55:59,440
I've got a purple line.

1137
00:55:59,440 --> 00:56:02,800
That's the Delft railway system
connecting all major cities

1138
00:56:02,800 --> 00:56:03,610
of the Netherlands.

1139
00:56:03,610 --> 00:56:05,860
If you get in Delft
central station,

1140
00:56:05,860 --> 00:56:08,590
within an hour you're
standing on the central market

1141
00:56:08,590 --> 00:56:11,800
in Amsterdam, within 10
minutes to 50 minutes

1142
00:56:11,800 --> 00:56:13,510
you're in Rotterdam
or The Hague.

1143
00:56:13,510 --> 00:56:18,377
Nationwide system very good
quality, 11 trains each hour

1144
00:56:18,377 --> 00:56:19,800
each direction.

1145
00:56:19,800 --> 00:56:22,090
So it's perfect.

1146
00:56:22,090 --> 00:56:24,940
If you live in Delft, you
can reach 1 million jobs

1147
00:56:24,940 --> 00:56:26,900
within 45 minutes.

1148
00:56:26,900 --> 00:56:32,340
So if you need a
place, live in Delft.

1149
00:56:32,340 --> 00:56:33,610
That's our first system.

1150
00:56:33,610 --> 00:56:37,080
The second one, if I asked
the people what do they like,

1151
00:56:37,080 --> 00:56:39,990
most people like
light rail like tram.

1152
00:56:39,990 --> 00:56:44,130
There's a large group of car
drivers who love light rail

1153
00:56:44,130 --> 00:56:45,300
and don't like buses.

1154
00:56:45,300 --> 00:56:49,340
So I tried to convert my
complete network to light rail.

1155
00:56:49,340 --> 00:56:51,590
That is the dotted
lines over here.

1156
00:56:51,590 --> 00:56:54,660
The red ones are already
built. And we're still

1157
00:56:54,660 --> 00:56:56,290
talking with the
regional government

1158
00:56:56,290 --> 00:56:58,830
to get funding
for the black one.

1159
00:56:58,830 --> 00:57:01,350
And if that's done,
you see a spider kind

1160
00:57:01,350 --> 00:57:04,810
of network covering
most of the city.

1161
00:57:04,810 --> 00:57:08,590
And I add some regional bus
lines through its radial lines.

1162
00:57:08,590 --> 00:57:10,992
That's the next
coverage of our system.

1163
00:57:10,992 --> 00:57:12,325
And that's the commuter network.

1164
00:57:16,580 --> 00:57:19,700
And that's the last network
covering everything.

1165
00:57:19,700 --> 00:57:22,380
Step on a bus, pay $2,
you've got the whole city

1166
00:57:22,380 --> 00:57:24,980
to view if you've got the time.

1167
00:57:24,980 --> 00:57:28,110
That's how we cover
the complete area.

1168
00:57:28,110 --> 00:57:32,130
And the last group is
transport on demand.

1169
00:57:32,130 --> 00:57:36,720
If you're unable to use a public
bus, we use smaller buses.

1170
00:57:36,720 --> 00:57:38,945
You have to phone
every one hour, search

1171
00:57:38,945 --> 00:57:42,780
a bus driving through, and you
were picked up and delivered

1172
00:57:42,780 --> 00:57:45,030
door to door transport.

1173
00:57:45,030 --> 00:57:49,100
It's a fantastic system
but it's awful expensive.

1174
00:57:49,100 --> 00:57:52,680
So what we're trying to do is
get people out of this system,

1175
00:57:52,680 --> 00:57:55,710
this market is growing,
and getting them back

1176
00:57:55,710 --> 00:57:56,640
in a normal bus.

1177
00:57:56,640 --> 00:57:59,640
So we modify the bus so they
are more attractive for people

1178
00:57:59,640 --> 00:58:02,610
with light handicaps.

1179
00:58:02,610 --> 00:58:04,650
And the other thing we
are thinking about, maybe

1180
00:58:04,650 --> 00:58:07,860
we can offer a discount to the
buses as a sort of timetable.

1181
00:58:07,860 --> 00:58:11,320
We have a line structure for
driving that kind of business.

1182
00:58:11,320 --> 00:58:13,230
So it looks like more
public transport which

1183
00:58:13,230 --> 00:58:18,230
makes it more cheaper to run.

1184
00:58:18,230 --> 00:58:20,590
Physical priority.

1185
00:58:20,590 --> 00:58:22,600
That's the first thing we do.

1186
00:58:22,600 --> 00:58:26,340
If a bus is in the same lane
as a car or if there's many

1187
00:58:26,340 --> 00:58:28,630
bicycles usually
there's the same speed,

1188
00:58:28,630 --> 00:58:31,265
and I cannot give
them any priority,

1189
00:58:31,265 --> 00:58:33,640
let's give them bus lines.

1190
00:58:36,490 --> 00:58:39,060
Where the center of city,
center is city Delft, that

1191
00:58:39,060 --> 00:58:41,380
is the downtown area, the
central market square,

1192
00:58:41,380 --> 00:58:43,870
this is where all the shops
are and all the restaurants.

1193
00:58:43,870 --> 00:58:45,490
That's the most
historical center.

1194
00:58:45,490 --> 00:58:47,455
It's a lovely place to be.

1195
00:58:47,455 --> 00:58:51,370
You see the square over there,
that is the central railroad

1196
00:58:51,370 --> 00:58:52,270
station.

1197
00:58:52,270 --> 00:58:55,020
If you'd like to leave
the city, go there.

1198
00:58:55,020 --> 00:58:56,620
And we designed
all the bus lines

1199
00:58:56,620 --> 00:58:59,440
going to the central
railroad station.

1200
00:58:59,440 --> 00:59:02,130
We can give them good
priority on that location.

1201
00:59:04,790 --> 00:59:06,920
When do we need a bus lane?

1202
00:59:06,920 --> 00:59:13,230
We need it if there is a delay
of driving with the cars.

1203
00:59:13,230 --> 00:59:15,790
So on busy streets I
like to have a bus lane.

1204
00:59:15,790 --> 00:59:19,640
And that's difficult because
if it's a busy street,

1205
00:59:19,640 --> 00:59:23,290
you need probably four lanes
or two lanes of car traffic.

1206
00:59:23,290 --> 00:59:26,470
And I'm asking one lane
for six or eight buses

1207
00:59:26,470 --> 00:59:28,340
per hour in each direction.

1208
00:59:28,340 --> 00:59:31,280
So then we have to compete, as
I said, in the busiest areas.

1209
00:59:31,280 --> 00:59:34,900
We start searching for a bus
lane or a light rail lane

1210
00:59:34,900 --> 00:59:37,180
so we can give them priority.

1211
00:59:37,180 --> 00:59:40,210
And elsewhere-- this
is a residential area,

1212
00:59:40,210 --> 00:59:44,880
it's nice to have but you
don't need to have it.

1213
00:59:44,880 --> 00:59:47,300
This was thought in
the 80s, OK, let's

1214
00:59:47,300 --> 00:59:49,880
make a bus lane everywhere
so we get the bus

1215
00:59:49,880 --> 00:59:51,830
lane in a residential area.

1216
00:59:51,830 --> 00:59:54,500
And the only place
we need it that it's

1217
00:59:54,500 --> 00:59:57,280
crossing the highway
in that location

1218
00:59:57,280 --> 00:59:59,976
is because that's our
big intersections.

1219
01:00:03,190 --> 01:00:09,960
Another part of priority is at
the central station of Delft.

1220
01:00:09,960 --> 01:00:11,895
This area, if you
look at Delft and you

1221
01:00:11,895 --> 01:00:14,210
take in Delft area,
urban development,

1222
01:00:14,210 --> 01:00:17,260
railroad you see a huge
development in the downtown

1223
01:00:17,260 --> 01:00:17,760
area.

1224
01:00:17,760 --> 01:00:20,790
Over here is the old station.

1225
01:00:20,790 --> 01:00:22,110
Over there is a new one.

1226
01:00:22,110 --> 01:00:26,380
We have spent 500 million Euros
to get the railroad tracks

1227
01:00:26,380 --> 01:00:29,970
under the ground
for 1 and 1/2 miles.

1228
01:00:29,970 --> 01:00:34,380
And we built a complete railroad
station, a new bus platform,

1229
01:00:34,380 --> 01:00:38,460
and we did a complete separation
of all the transfer flows.

1230
01:00:38,460 --> 01:00:41,695
On the surface level we
offered public transport.

1231
01:00:41,695 --> 01:00:44,670
So in the open air,
that's public transport.

1232
01:00:44,670 --> 01:00:47,130
On minus one, in
the basement, we

1233
01:00:47,130 --> 01:00:50,850
have the huge parking
facility with parking lanes

1234
01:00:50,850 --> 01:00:53,020
underground to bus platform.

1235
01:00:53,020 --> 01:00:56,580
So we have a physical
separation of the bike transport

1236
01:00:56,580 --> 01:00:59,505
going to the railroad station
and the bus transport.

1237
01:00:59,505 --> 01:01:03,270
Now on level minus two, we
have the railroad tracks.

1238
01:01:03,270 --> 01:01:06,510
That's one way of separation.

1239
01:01:06,510 --> 01:01:10,690
You can see it here
in the picture.

1240
01:01:10,690 --> 01:01:12,640
This is the town hall,
the glass building.

1241
01:01:12,640 --> 01:01:14,494
And the first floor,
the ground floor,

1242
01:01:14,494 --> 01:01:15,660
that's the railroad station.

1243
01:01:15,660 --> 01:01:18,100
We have the name Delft on it.

1244
01:01:18,100 --> 01:01:19,960
And underneath in
it right, you can

1245
01:01:19,960 --> 01:01:24,340
see people standing at the
entrance of the parking garage.

1246
01:01:24,340 --> 01:01:27,760
We've got 100,000
people living in Delft.

1247
01:01:27,760 --> 01:01:31,480
This parking garage for
bicycles is today 8,000 places,

1248
01:01:31,480 --> 01:01:33,520
and it's not enough.

1249
01:01:33,520 --> 01:01:36,260
So a few years later there
will be 10,000 places

1250
01:01:36,260 --> 01:01:39,270
for 100,000 residents.

1251
01:01:39,270 --> 01:01:41,337
So bike parking
is very important.

1252
01:01:41,337 --> 01:01:43,170
AUDIENCE: There's also
the university there,

1253
01:01:43,170 --> 01:01:47,181
so they're not all residents.

1254
01:01:47,181 --> 01:01:47,680
Yeah.

1255
01:01:47,680 --> 01:01:49,817
Not all the students are
residents [INAUDIBLE]..

1256
01:01:49,817 --> 01:01:50,650
JAN NEDERVEEN: Yeah.

1257
01:01:50,650 --> 01:01:51,490
It's students.

1258
01:01:51,490 --> 01:01:52,531
It's also residents now.

1259
01:01:52,531 --> 01:01:53,030
Yes.

1260
01:01:53,030 --> 01:01:54,670
OK.

1261
01:01:54,670 --> 01:02:00,230
But when the students
are at the university

1262
01:02:00,230 --> 01:02:04,360
and you look at the parking
facility, it's also full.

1263
01:02:04,360 --> 01:02:06,400
And other people leaving Delft.

1264
01:02:06,400 --> 01:02:09,250
Some of them are
also students going

1265
01:02:09,250 --> 01:02:12,250
into a university in
Leiden or in Rotterdam

1266
01:02:12,250 --> 01:02:16,480
but also normal people like
myself are parking there.

1267
01:02:16,480 --> 01:02:19,540
It's not a student
parking garage.

1268
01:02:19,540 --> 01:02:21,070
Yeah.

1269
01:02:21,070 --> 01:02:24,780
It's true that a large
group of them are students.

1270
01:02:24,780 --> 01:02:27,570
Well minus one is for the
bikes and the bus platform

1271
01:02:27,570 --> 01:02:29,940
is operational on this level.

1272
01:02:29,940 --> 01:02:34,900
So buses don't have to deal
with cars or with pedestrians

1273
01:02:34,900 --> 01:02:36,300
or with bikes.

1274
01:02:36,300 --> 01:02:37,094
Yes.

1275
01:02:37,094 --> 01:02:39,070
AUDIENCE: So if minus
one is parking for bikes,

1276
01:02:39,070 --> 01:02:44,510
do they also travel on that
level or do they [INAUDIBLE]??

1277
01:02:44,510 --> 01:02:47,280
JAN NEDERVEEN: The bikes
also travel on minus one.

1278
01:02:47,280 --> 01:02:51,180
The bike lane goes
here under this bridge

1279
01:02:51,180 --> 01:02:52,570
and then entering the park.

1280
01:02:52,570 --> 01:02:54,750
You can see there's
a rim over it.

1281
01:02:54,750 --> 01:02:57,390
So he has a complete
separation to minus one

1282
01:02:57,390 --> 01:03:01,640
in the most busiest area.

1283
01:03:01,640 --> 01:03:04,630
And that saves me a lot of
time because the first traffic

1284
01:03:04,630 --> 01:03:07,620
light, very close to
the railroad station,

1285
01:03:07,620 --> 01:03:12,700
should otherwise have to deal
with 10,000 bicycles a day.

1286
01:03:12,700 --> 01:03:14,350
But I've offered
them a tunnel so I've

1287
01:03:14,350 --> 01:03:17,050
got a normal intersection
with a normal traffic light.

1288
01:03:17,050 --> 01:03:20,880
All the rest I cannot handle
that amount of cyclists,

1289
01:03:20,880 --> 01:03:24,100
and this Peter here among
this group, he will not stop.

1290
01:03:27,970 --> 01:03:29,870
Here's an aerial
view of the system.

1291
01:03:29,870 --> 01:03:31,630
The town hall is in the front.

1292
01:03:31,630 --> 01:03:33,860
And we have also an
east-west separation.

1293
01:03:33,860 --> 01:03:38,190
On the down inner city
side that's over here,

1294
01:03:38,190 --> 01:03:42,560
we put the bus lane,
the light rail lane.

1295
01:03:42,560 --> 01:03:46,810
And on the other side, we've got
the lane with the car traffic.

1296
01:03:46,810 --> 01:03:48,870
And that's very important
because at the top

1297
01:03:48,870 --> 01:03:51,420
of the picture on
the left side, I

1298
01:03:51,420 --> 01:03:54,120
have an intersection where all
public transport has to make

1299
01:03:54,120 --> 01:03:56,436
all the left or right turns.

1300
01:03:56,436 --> 01:03:57,810
And that's the
only one that make

1301
01:03:57,810 --> 01:04:00,320
that turn because the
car route is blocked

1302
01:04:00,320 --> 01:04:02,820
and the bike lane is
underground in a tunnel.

1303
01:04:02,820 --> 01:04:06,330
So I have an intersection
where only public transport

1304
01:04:06,330 --> 01:04:08,539
makes left and right turns.

1305
01:04:08,539 --> 01:04:10,830
And on the other intersection
that's almost falling off

1306
01:04:10,830 --> 01:04:12,288
the picture on the
right side, that

1307
01:04:12,288 --> 01:04:17,040
is my car intersection where
all the light rail traffic only

1308
01:04:17,040 --> 01:04:19,520
has to cross, they
go straight through.

1309
01:04:19,520 --> 01:04:23,430
So it was much easier to handle
if a separate public transport

1310
01:04:23,430 --> 01:04:26,950
and car transport on
different intersections.

1311
01:04:26,950 --> 01:04:31,000
And my transport engineers were
interested in traffic lights.

1312
01:04:31,000 --> 01:04:33,550
I took them, let me have a
look if this is the same.

1313
01:04:33,550 --> 01:04:37,900
Can you build a traffic
light for this location?

1314
01:04:37,900 --> 01:04:41,680
Because the alternative was one
big crossing with everything,

1315
01:04:41,680 --> 01:04:44,900
and that didn't work.

1316
01:04:44,900 --> 01:04:48,830
I do also have some discussions
with my urban planners.

1317
01:04:48,830 --> 01:04:52,610
And they love the light rail and
the green grass in the middle.

1318
01:04:55,480 --> 01:05:01,230
And my public
transport here, lots

1319
01:05:01,230 --> 01:05:07,090
of asphalt. What do you like?

1320
01:05:07,090 --> 01:05:08,980
I pick you out.

1321
01:05:08,980 --> 01:05:12,000
Which one would
you like and why?

1322
01:05:12,000 --> 01:05:15,920
AUDIENCE: I'd prefer the
light lines because I feel

1323
01:05:15,920 --> 01:05:18,370
like you're more in tune with--

1324
01:05:18,370 --> 01:05:22,520
you experience the
road better that way.

1325
01:05:22,520 --> 01:05:24,120
You can serve the
demand like that.

1326
01:05:24,120 --> 01:05:25,324
You should go green.

1327
01:05:25,324 --> 01:05:26,740
JAN NEDERVEEN: So
which one do you

1328
01:05:26,740 --> 01:05:28,865
like, the light rail in
the green or the light rail

1329
01:05:28,865 --> 01:05:30,182
in the asphalt?

1330
01:05:30,182 --> 01:05:32,184
AUDIENCE: In the green.

1331
01:05:32,184 --> 01:05:33,350
JAN NEDERVEEN: In the green.

1332
01:05:33,350 --> 01:05:36,035
It's lovely, nicer.

1333
01:05:36,035 --> 01:05:36,910
AUDIENCE: [INAUDIBLE]

1334
01:05:36,910 --> 01:05:37,743
JAN NEDERVEEN: Yeah.

1335
01:05:37,743 --> 01:05:40,100
Well we had that
discussion also.

1336
01:05:40,100 --> 01:05:43,270
I also think the top picture
is the most beautiful.

1337
01:05:43,270 --> 01:05:46,940
But this has one
big disadvantage.

1338
01:05:46,940 --> 01:05:51,030
If I have a bus link or
a public transport link

1339
01:05:51,030 --> 01:05:55,220
but I like to operate buses
as well as light rail,

1340
01:05:55,220 --> 01:05:59,720
in this situation they can
both use the same line.

1341
01:05:59,720 --> 01:06:01,550
And I've got one
platform, and you

1342
01:06:01,550 --> 01:06:04,720
can decide if you take
a bus or light rail.

1343
01:06:04,720 --> 01:06:08,780
And the one on top, if I would
like to add the bus lane,

1344
01:06:08,780 --> 01:06:12,260
well that would be a bus
stop without priority

1345
01:06:12,260 --> 01:06:14,300
on the normal street.

1346
01:06:14,300 --> 01:06:15,740
I [INAUDIBLE] that
one because it

1347
01:06:15,740 --> 01:06:18,560
doesn't have a bus lane
anymore because I replaced it

1348
01:06:18,560 --> 01:06:19,240
by a light rail.

1349
01:06:22,120 --> 01:06:22,760
Yes.

1350
01:06:22,760 --> 01:06:25,970
AUDIENCE: What is the typical
frequency of light rail lines?

1351
01:06:25,970 --> 01:06:28,810
JAN NEDERVEEN: The minimum
is four light rail vehicles

1352
01:06:28,810 --> 01:06:29,950
an hour each direction.

1353
01:06:29,950 --> 01:06:31,670
That's the minimum.

1354
01:06:31,670 --> 01:06:32,170
Otherwise--

1355
01:06:32,170 --> 01:06:33,540
AUDIENCE: Rush hour?

1356
01:06:33,540 --> 01:06:37,080
JAN NEDERVEEN: It goes
up to 6 or 8 in Delft.

1357
01:06:37,080 --> 01:06:39,920
And in other cities
it can be more.

1358
01:06:39,920 --> 01:06:44,770
But eight is all pretty much
for city with 100,000 people.

1359
01:06:44,770 --> 01:06:47,470
And it has to
compete with cycling.

1360
01:06:47,470 --> 01:06:50,710
So many people who
cycle you take them out

1361
01:06:50,710 --> 01:06:54,180
from the public
transport system.

1362
01:06:54,180 --> 01:06:58,490
These guys, cab
drivers always ask me,

1363
01:06:58,490 --> 01:07:01,250
may I use your bus lanes?

1364
01:07:01,250 --> 01:07:05,030
Because they are so fast and
they have beautiful traffic

1365
01:07:05,030 --> 01:07:06,230
lights.

1366
01:07:06,230 --> 01:07:09,700
I couldn't find a letter
size bigger than this one.

1367
01:07:12,740 --> 01:07:14,240
I said no!

1368
01:07:14,240 --> 01:07:16,720
Absolutely not!

1369
01:07:16,720 --> 01:07:22,740
I've got maybe 2018 cabs
in Delft, but it's no, no.

1370
01:07:22,740 --> 01:07:25,627
AUDIENCE: It's not more
efficient than driving.

1371
01:07:25,627 --> 01:07:27,460
JAN NEDERVEEN: Oh, they
love to drive my bus

1372
01:07:27,460 --> 01:07:30,160
lanes like the fire
department, who is pretty fast,

1373
01:07:30,160 --> 01:07:34,360
but no way I want it.

1374
01:07:34,360 --> 01:07:38,530
Because if they enter
a huge intersection

1375
01:07:38,530 --> 01:07:41,260
and there is a bus going
at that intersection,

1376
01:07:41,260 --> 01:07:44,620
I know that bus will
make a left turn.

1377
01:07:44,620 --> 01:07:47,680
Because every bus on that
intersection will make a left

1378
01:07:47,680 --> 01:07:48,620
turn.

1379
01:07:48,620 --> 01:07:52,970
And that means all other
directions can get green.

1380
01:07:52,970 --> 01:07:55,736
I don't know where
that cab is going.

1381
01:07:55,736 --> 01:07:59,810
So you have to completely block
the intersection for one cab.

1382
01:07:59,810 --> 01:08:00,560
Yes?

1383
01:08:00,560 --> 01:08:04,851
AUDIENCE: Why is that London
lets taxis use the bus lanes?

1384
01:08:04,851 --> 01:08:06,830
Are you familiar with that?

1385
01:08:06,830 --> 01:08:08,020
JAN NEDERVEEN: In London?

1386
01:08:08,020 --> 01:08:08,644
AUDIENCE: Yeah.

1387
01:08:08,644 --> 01:08:11,150
JAN NEDERVEEN: Yeah,
maybe they block out

1388
01:08:11,150 --> 01:08:15,270
all the other directions
to give them the priority.

1389
01:08:15,270 --> 01:08:19,229
And that will seriously harm
all other modes of transport.

1390
01:08:19,229 --> 01:08:23,290
It would harm car
traffic and bike traffic.

1391
01:08:23,290 --> 01:08:27,560
And we like to give priority
to the buses with many people,

1392
01:08:27,560 --> 01:08:29,290
but this is one
taxi who have maybe

1393
01:08:29,290 --> 01:08:30,990
one or two people inside it.

1394
01:08:30,990 --> 01:08:34,015
That's not worth the effort.

1395
01:08:34,015 --> 01:08:36,090
And it's a big risk
to give him green

1396
01:08:36,090 --> 01:08:37,454
and see what is happening.

1397
01:08:41,170 --> 01:08:41,950
Time priority.

1398
01:08:41,950 --> 01:08:46,340
Peter already taught some
things but that is what we do.

1399
01:08:46,340 --> 01:08:49,689
You have special traffic
lights, the [INAUDIBLE] traffic

1400
01:08:49,689 --> 01:08:56,580
lights that's in the picture on
the black/white border column.

1401
01:08:56,580 --> 01:08:59,890
That's showing if you get green
to left or to right or straight

1402
01:08:59,890 --> 01:09:01,340
through for our bus.

1403
01:09:01,340 --> 01:09:04,990
And we have two
kinds of detection.

1404
01:09:04,990 --> 01:09:07,270
The first one is
the intelligent one.

1405
01:09:07,270 --> 01:09:13,189
So every vehicle says,
I'm bus 24 vehicle number,

1406
01:09:13,189 --> 01:09:18,520
so I should be here
20 minutes past five.

1407
01:09:18,520 --> 01:09:21,439
So it's also telling
it's time per table.

1408
01:09:21,439 --> 01:09:25,300
And then we know, OK,
you're one minute early,

1409
01:09:25,300 --> 01:09:29,979
we will not give you priority
That's the expensive one.

1410
01:09:29,979 --> 01:09:32,720
And the other one, that's
a simple detection.

1411
01:09:32,720 --> 01:09:35,080
Some vehicle is crossing
a detector and notice, oh,

1412
01:09:35,080 --> 01:09:36,490
this is a vehicle.

1413
01:09:36,490 --> 01:09:37,960
I even don't know
which bus it is.

1414
01:09:37,960 --> 01:09:40,450
Even if you are a
car you are detected

1415
01:09:40,450 --> 01:09:42,640
and then you get some priority.

1416
01:09:42,640 --> 01:09:44,200
That's the way of detection.

1417
01:09:44,200 --> 01:09:45,399
The top one is the best.

1418
01:09:45,399 --> 01:09:48,460
So if we are in charge and
it's our traffic light,

1419
01:09:48,460 --> 01:09:50,439
we put in the intelligent one.

1420
01:09:50,439 --> 01:09:52,390
If somebody is else
doing the design,

1421
01:09:52,390 --> 01:09:55,610
a regional government,
sometimes you get the cheap one.

1422
01:09:55,610 --> 01:09:58,960
Especially in the Delft
University, top technology

1423
01:09:58,960 --> 01:10:01,480
campus, the cheap
one is installed.

1424
01:10:04,630 --> 01:10:05,840
Traffic light priority.

1425
01:10:05,840 --> 01:10:10,120
Peter showed you a bus stop
close to an intersection.

1426
01:10:10,120 --> 01:10:14,360
Well, here's an example of
a traffic light priority

1427
01:10:14,360 --> 01:10:16,070
at a huge intersection.

1428
01:10:16,070 --> 01:10:19,170
The term has to make
a turn to the left.

1429
01:10:19,170 --> 01:10:23,550
And what we do, we
put in to two lines.

1430
01:10:23,550 --> 01:10:26,220
The first one is
the location where

1431
01:10:26,220 --> 01:10:29,940
the light rail, the [AUDIO OUT]
for handling the passengers.

1432
01:10:29,940 --> 01:10:33,770
I don't know how
long that will take.

1433
01:10:33,770 --> 01:10:36,540
And I don't want to stop all
the other traffic because he

1434
01:10:36,540 --> 01:10:37,850
is still handling passengers.

1435
01:10:37,850 --> 01:10:40,400
If I do so, I get many
letters from people

1436
01:10:40,400 --> 01:10:41,970
waiting for nothing.

1437
01:10:41,970 --> 01:10:44,270
So there's a second
stop line, go

1438
01:10:44,270 --> 01:10:46,850
straightforward on
the intersection.

1439
01:10:46,850 --> 01:10:49,530
And then the light
rail will [INAUDIBLE],,

1440
01:10:49,530 --> 01:10:51,350
hey, hello I'm here.

1441
01:10:51,350 --> 01:10:54,220
Please can you give
me what priority.

1442
01:10:54,220 --> 01:10:57,560
And what this system does,
he will not break off

1443
01:10:57,560 --> 01:10:58,610
all the other signals.

1444
01:10:58,610 --> 01:11:00,900
He says, oh, I've
finished my phase,

1445
01:11:00,900 --> 01:11:04,370
I then add in the phase
with public transport,

1446
01:11:04,370 --> 01:11:06,530
and then I continue
with all the rest.

1447
01:11:06,530 --> 01:11:09,260
I don't take out any
time from the others,

1448
01:11:09,260 --> 01:11:13,410
just merge in a priority
for the traffic lights.

1449
01:11:13,410 --> 01:11:15,395
So this intersection
is four phases

1450
01:11:15,395 --> 01:11:18,300
so there are four chances
to give him priority.

1451
01:11:18,300 --> 01:11:21,710
So the waiting time is
not a full cycle but only

1452
01:11:21,710 --> 01:11:24,360
a quarter of it.

1453
01:11:24,360 --> 01:11:26,860
That's how it works.

1454
01:11:26,860 --> 01:11:31,510
This is that same
intersection from the air.

1455
01:11:31,510 --> 01:11:33,640
So it's a huge one, the
biggest intersection

1456
01:11:33,640 --> 01:11:35,543
we have in the built up area.

1457
01:11:35,543 --> 01:11:38,440
We have total detection
all directions.

1458
01:11:38,440 --> 01:11:41,950
Also the bicycles are detected.

1459
01:11:41,950 --> 01:11:43,000
We have a detector.

1460
01:11:43,000 --> 01:11:44,020
We don't use an eight.

1461
01:11:44,020 --> 01:11:46,010
We've got a good detector.

1462
01:11:46,010 --> 01:11:48,190
So we detect bikes.

1463
01:11:48,190 --> 01:11:51,070
There also is a button if you
like, but most of the time

1464
01:11:51,070 --> 01:11:53,290
you're already detected.

1465
01:11:53,290 --> 01:11:59,010
We have a fixed sequence
which groups go together.

1466
01:11:59,010 --> 01:12:01,190
And what the sequence is?

1467
01:12:01,190 --> 01:12:04,460
We have defined a
maximum green time

1468
01:12:04,460 --> 01:12:07,440
that might be possible
for each direction.

1469
01:12:07,440 --> 01:12:11,960
And we stop giving green if we
achieve a free flow situation.

1470
01:12:11,960 --> 01:12:15,830
So I don't give green
to free flow traffic.

1471
01:12:15,830 --> 01:12:17,490
And if the traffic's
still congested

1472
01:12:17,490 --> 01:12:20,570
after a certain amount of time
we say, OK, now it's enough,

1473
01:12:20,570 --> 01:12:23,560
now the others have to go.

1474
01:12:23,560 --> 01:12:26,950
You have bus priority and light
rail priority and fire truck

1475
01:12:26,950 --> 01:12:28,420
priority.

1476
01:12:28,420 --> 01:12:31,090
And we don't build
intersections in Delft.

1477
01:12:31,090 --> 01:12:34,720
We have a traffic light
sequence of 120 seconds.

1478
01:12:34,720 --> 01:12:36,160
That's the max.

1479
01:12:36,160 --> 01:12:39,610
So if the area is congested,
the maximum cycle time

1480
01:12:39,610 --> 01:12:42,610
is 1 minute and 20 seconds.

1481
01:12:42,610 --> 01:12:46,700
And my [INAUDIBLE] if you
look at our intersections,

1482
01:12:46,700 --> 01:12:48,770
I'm trying to bring
back the cycle

1483
01:12:48,770 --> 01:12:55,050
time for as many intersections
back to 90 seconds.

1484
01:12:55,050 --> 01:12:57,660
And they did and for most
intersections it worked.

1485
01:12:57,660 --> 01:13:01,260
And it was a huge
benefit for everybody.

1486
01:13:01,260 --> 01:13:04,840
The maximum waiting time
is reduced 30 seconds.

1487
01:13:04,840 --> 01:13:07,650
So if you missed going
first 30 seconds,

1488
01:13:07,650 --> 01:13:10,420
you're simply reducing
the cycle time.

1489
01:13:10,420 --> 01:13:12,000
You can also do it
physically, make

1490
01:13:12,000 --> 01:13:14,790
your intersections smaller.

1491
01:13:14,790 --> 01:13:17,776
That's a huge benefit
for the cycling time.

1492
01:13:17,776 --> 01:13:20,870
And we noticed
some intersections

1493
01:13:20,870 --> 01:13:23,370
were pretty sharp, 90 seconds.

1494
01:13:23,370 --> 01:13:25,150
People get used to
it so they didn't

1495
01:13:25,150 --> 01:13:27,340
miss the first second of green.

1496
01:13:27,340 --> 01:13:30,120
They were green,
[INAUDIBLE],, driving.

1497
01:13:30,120 --> 01:13:33,860
So we could handle the
same number of cars

1498
01:13:33,860 --> 01:13:35,890
in a shorter green time.

1499
01:13:35,890 --> 01:13:39,880
A special one was the
fire truck priority.

1500
01:13:39,880 --> 01:13:43,980
The fire department has a depot
exactly at that intersection.

1501
01:13:43,980 --> 01:13:46,910
And they've got a
beautiful red button.

1502
01:13:46,910 --> 01:13:49,870
So if I press that red
button, the intersection

1503
01:13:49,870 --> 01:13:53,410
will stand in a way that
the order directions

1504
01:13:53,410 --> 01:13:57,490
are blocked that the fire
department has to cross.

1505
01:13:57,490 --> 01:13:59,770
So if you're not in
the direction of a fire

1506
01:13:59,770 --> 01:14:01,810
that the fire
department has to go,

1507
01:14:01,810 --> 01:14:06,130
you still get green because it
is an intelligence red button.

1508
01:14:06,130 --> 01:14:10,090
So I press this button showing
I have a fire in Delft North,

1509
01:14:10,090 --> 01:14:12,880
and they will follow this route.

1510
01:14:12,880 --> 01:14:15,810
Then that route will get
green for the fire truck

1511
01:14:15,810 --> 01:14:18,190
on the time we think
he will be there.

1512
01:14:18,190 --> 01:14:21,950
So while driving North,
he continues detected,

1513
01:14:21,950 --> 01:14:24,750
and the traffic lights
are switched that way

1514
01:14:24,750 --> 01:14:27,000
that we will get green.

1515
01:14:27,000 --> 01:14:30,270
We do not block completely
all these intersections

1516
01:14:30,270 --> 01:14:32,910
for the fire trucks since
he knows if we do so,

1517
01:14:32,910 --> 01:14:36,180
we might cause a traffic jam
because all the directions

1518
01:14:36,180 --> 01:14:37,680
are blocked.

1519
01:14:37,680 --> 01:14:39,180
And that's the way
how we get there.

1520
01:14:39,180 --> 01:14:43,410
And we also detect if you
pressed the right button

1521
01:14:43,410 --> 01:14:47,225
and if we make a system that is
going perfectly to the north.

1522
01:14:47,225 --> 01:14:51,020
Maybe he didn't use that
route but in certain times

1523
01:14:51,020 --> 01:14:53,590
the system arguments,
OK, I did the measuring

1524
01:14:53,590 --> 01:14:57,160
so somebody has disappeared
or gone somewhere else.

1525
01:14:57,160 --> 01:14:59,470
Well let's switch
back to normal.

1526
01:14:59,470 --> 01:15:01,760
That's the fire priority
we've got in Delft.

1527
01:15:01,760 --> 01:15:05,160
And it was very important when
we built the railroad tunnel

1528
01:15:05,160 --> 01:15:09,540
because the whole area
was under construction

1529
01:15:09,540 --> 01:15:12,633
with all the traffic lights
kept to that priority.

1530
01:15:15,580 --> 01:15:17,481
And that's the
example from Delft.

1531
01:15:17,481 --> 01:15:17,980
Thank you.

1532
01:15:24,354 --> 01:15:25,520
PETER FURTH: My new graphic.

1533
01:15:29,130 --> 01:15:29,630
Yeah.

1534
01:15:35,380 --> 01:15:41,050
So I told you that [AUDIO OUT]
are green extension, which

1535
01:15:41,050 --> 01:15:43,240
is great if you've
got a far side stop

1536
01:15:43,240 --> 01:15:44,650
and you can predict events.

1537
01:15:44,650 --> 01:15:46,900
Early green, which is
a little more limited

1538
01:15:46,900 --> 01:15:48,440
but we need more flexibility.

1539
01:15:48,440 --> 01:15:51,010
So like what Jan was
describing there,

1540
01:15:51,010 --> 01:15:56,270
they have these four
phases in the cycle.

1541
01:15:56,270 --> 01:15:58,700
To make it simple,
let's just say

1542
01:15:58,700 --> 01:16:07,820
we have east and west left
and then east and west through

1543
01:16:07,820 --> 01:16:14,710
and then north and south
left and north and south

1544
01:16:14,710 --> 01:16:20,580
through, phase one, two,
three, four, and the tram,

1545
01:16:20,580 --> 01:16:22,110
in this case,
because it actually

1546
01:16:22,110 --> 01:16:23,830
conflicts with all of them.

1547
01:16:23,830 --> 01:16:28,140
So the normal thinking of a
traffic engineer would be,

1548
01:16:28,140 --> 01:16:30,534
OK, and then we'll
have a tram phase here.

1549
01:16:30,534 --> 01:16:31,575
And now that's the cycle.

1550
01:16:34,540 --> 01:16:37,475
But the Delft thinking is,
we'll put a tram phase here,

1551
01:16:37,475 --> 01:16:39,850
we'll put a tram phase here,
we'll put a tram phase here,

1552
01:16:39,850 --> 01:16:41,650
and a tram phase here.

1553
01:16:41,650 --> 01:16:43,390
And if there's no
tram, well we skip it.

1554
01:16:43,390 --> 01:16:46,060
And if there is a tram,
then the tram gets to go.

1555
01:16:46,060 --> 01:16:48,460
So the tram never
has to wait long.

1556
01:16:48,460 --> 01:16:52,480
So that's part of the, if we
can get a man on the moon,

1557
01:16:52,480 --> 01:16:54,890
we can turn the light green.

1558
01:16:54,890 --> 01:17:01,710
So let me say something.

1559
01:17:01,710 --> 01:17:04,090
I'll leave the rest
of these plans.

1560
01:17:04,090 --> 01:17:06,330
They have some details there.

1561
01:17:06,330 --> 01:17:09,720
But let me tell you something
about D Street and the Silver

1562
01:17:09,720 --> 01:17:11,580
Line, OK?

1563
01:17:11,580 --> 01:17:17,622
So the Waterfront Silver Line--

1564
01:17:17,622 --> 01:17:19,740
AUDIENCE: [INAUDIBLE]

1565
01:17:19,740 --> 01:17:20,448
PETER FURTH: Huh?

1566
01:17:20,448 --> 01:17:21,700
AUDIENCE: Do you have a video?

1567
01:17:21,700 --> 01:17:22,533
PETER FURTH: No, no.

1568
01:17:22,533 --> 01:17:25,000
I'm not going to do the video.

1569
01:17:25,000 --> 01:17:27,490
This is something new.

1570
01:17:27,490 --> 01:17:29,740
How many of you are familiar
with the Silver Line that

1571
01:17:29,740 --> 01:17:31,260
goes to and from the airport?

1572
01:17:31,260 --> 01:17:33,130
Yeah.

1573
01:17:33,130 --> 01:17:35,470
D street is where, if you're
going toward the airport,

1574
01:17:35,470 --> 01:17:38,707
it comes out of the tunnel and
then it stops at a red light.

1575
01:17:38,707 --> 01:17:41,040
And while you're waiting at
the red light you can watch,

1576
01:17:41,040 --> 01:17:42,310
and there's no cars going by.

1577
01:17:42,310 --> 01:17:44,180
And you think, why
is the light red?

1578
01:17:44,180 --> 01:17:50,140
So on a map here's
Congress Street.

1579
01:17:52,720 --> 01:17:55,120
This is D Street.

1580
01:17:55,120 --> 01:17:58,180
And then this is
Silver Line Way.

1581
01:17:58,180 --> 01:18:00,970
So the traffic
engineers are concerned

1582
01:18:00,970 --> 01:18:02,800
that that's a short distance.

1583
01:18:02,800 --> 01:18:05,320
And if they turn the light
red for Congress Street,

1584
01:18:05,320 --> 01:18:06,890
two bad things can happen.

1585
01:18:06,890 --> 01:18:08,680
One is spill back.

1586
01:18:08,680 --> 01:18:11,770
Traffic comes to here,
oh, the light is red,

1587
01:18:11,770 --> 01:18:16,240
and now queue spills back,
and it hurts the capacity.

1588
01:18:16,240 --> 01:18:18,880
And the second
one is starvation.

1589
01:18:18,880 --> 01:18:22,480
The light turns green here
for northbound traffic,

1590
01:18:22,480 --> 01:18:24,580
but the light is still red here.

1591
01:18:24,580 --> 01:18:28,430
So cars start to go, but nobody
can go because they're stuck.

1592
01:18:28,430 --> 01:18:29,620
It's starved.

1593
01:18:29,620 --> 01:18:35,410
So they don't want to
close D Street while either

1594
01:18:35,410 --> 01:18:37,280
of those things can happen.

1595
01:18:37,280 --> 01:18:40,330
So there is a cycle;
it's a 120 second cycle.

1596
01:18:40,330 --> 01:18:42,370
This time I'll draw
the cycle in a circle.

1597
01:18:42,370 --> 01:18:44,380
And they've decided
here is the time

1598
01:18:44,380 --> 01:18:46,790
in the cycle the bus can go.

1599
01:18:46,790 --> 01:18:48,970
So that's why you just
wait, you just wait.

1600
01:18:48,970 --> 01:18:52,870
You arrive and you just wait
until your time in the cycle.

1601
01:18:52,870 --> 01:18:55,660
So I just recently
had some students

1602
01:18:55,660 --> 01:18:59,380
study it in my advanced
traffic control class.

1603
01:18:59,380 --> 01:19:01,870
We actually took the whole
class there for a field trip

1604
01:19:01,870 --> 01:19:05,350
during morning peak hour
because I had to see it myself.

1605
01:19:05,350 --> 01:19:08,530
Is it really the disaster
people talk about?

1606
01:19:08,530 --> 01:19:10,000
It is not a traffic disaster.

1607
01:19:10,000 --> 01:19:14,980
It is a transit disaster because
the frequency the Silver Line,

1608
01:19:14,980 --> 01:19:16,629
it's about one bus
every two minutes,

1609
01:19:16,629 --> 01:19:17,920
and they go in both directions.

1610
01:19:17,920 --> 01:19:22,870
So that means in a
120 second cycle,

1611
01:19:22,870 --> 01:19:24,310
if they're perfectly
on schedule,

1612
01:19:24,310 --> 01:19:26,610
you'd have one bus at
most one per direction.

1613
01:19:26,610 --> 01:19:27,670
Of course they're not.

1614
01:19:27,670 --> 01:19:29,470
So often you've got
two buses, sometimes

1615
01:19:29,470 --> 01:19:32,004
three buses waiting to go.

1616
01:19:32,004 --> 01:19:34,042
And they wait, and they
wait, and they wait,

1617
01:19:34,042 --> 01:19:35,500
and they wait, and
most of the time

1618
01:19:35,500 --> 01:19:37,450
there is no conflicting traffic.

1619
01:19:37,450 --> 01:19:42,050
So my students learn how
to do traffic simulations.

1620
01:19:42,050 --> 01:19:43,990
There's some standard
packages for that.

1621
01:19:43,990 --> 01:19:46,670
They learn how to program
their own traffic control.

1622
01:19:46,670 --> 01:19:51,910
And they said, let's try just
all out aggressive priority.

1623
01:19:51,910 --> 01:19:55,090
When we detect the bus,
we just stop the street,

1624
01:19:55,090 --> 01:19:56,800
let the bus go through.

1625
01:19:56,800 --> 01:20:01,840
The bus only needs like 14
seconds, and then it goes back.

1626
01:20:01,840 --> 01:20:05,210
And I can hear
people saying, oh,

1627
01:20:05,210 --> 01:20:08,290
but sometimes you've got to
serve two or three buses.

1628
01:20:08,290 --> 01:20:11,630
Yeah, when buses have to wait
two minutes till their turn

1629
01:20:11,630 --> 01:20:12,130
comes.

1630
01:20:12,130 --> 01:20:14,200
But when they
don't have to wait,

1631
01:20:14,200 --> 01:20:16,580
you're never going to be
serving more than one at a time.

1632
01:20:16,580 --> 01:20:19,210
And it only takes 15 seconds.

1633
01:20:19,210 --> 01:20:21,280
We put that into the
simulation to see, OK,

1634
01:20:21,280 --> 01:20:23,080
how's it going to affect cars?

1635
01:20:23,080 --> 01:20:26,070
How is it going to affect buses?

1636
01:20:26,070 --> 01:20:29,430
Average delay for bus
goes from 50 seconds down

1637
01:20:29,430 --> 01:20:31,330
to four seconds.

1638
01:20:31,330 --> 01:20:33,140
Why four?

1639
01:20:33,140 --> 01:20:36,020
That's only because if we do
turn the light green for a bus,

1640
01:20:36,020 --> 01:20:40,664
for the cars a minimum 20
second before the next bus.

1641
01:20:40,664 --> 01:20:42,080
So there's a bus
in one direction,

1642
01:20:42,080 --> 01:20:44,020
the bus coming in
the other direction

1643
01:20:44,020 --> 01:20:47,920
15 seconds later might
have to wait a few seconds.

1644
01:20:47,920 --> 01:20:50,120
So delay for bus goes
down almost zero.

1645
01:20:50,120 --> 01:20:55,140
Delay for cars also goes
down because the system

1646
01:20:55,140 --> 01:20:59,662
they have now will stop the
cars even when there's no bus.

1647
01:21:03,540 --> 01:21:06,440
I don't know why.

1648
01:21:06,440 --> 01:21:08,960
And there's another thing
about the system they have now

1649
01:21:08,960 --> 01:21:10,410
that is not so intelligent.

1650
01:21:10,410 --> 01:21:16,390
So the main message
I want to get across

1651
01:21:16,390 --> 01:21:22,780
is the old way I said is if
we can put a man on the moon,

1652
01:21:22,780 --> 01:21:25,960
we can get the light to
turn green for the bus.

1653
01:21:25,960 --> 01:21:32,020
That is if you use
intelligent tactics,

1654
01:21:32,020 --> 01:21:35,350
we can almost always
reduce the delay

1655
01:21:35,350 --> 01:21:39,910
for a bus down to near
zero without really

1656
01:21:39,910 --> 01:21:42,290
increasing the delay for cars.

1657
01:21:42,290 --> 01:21:44,790
Bus only needs a few
seconds to get through.

1658
01:21:44,790 --> 01:21:47,720
They just need a few
seconds at the right time.

1659
01:21:47,720 --> 01:21:50,810
Just rearrange the
time a little bit.

1660
01:21:50,810 --> 01:21:53,960
Give the bus the
green when it needs.

1661
01:21:53,960 --> 01:21:57,740
And what's in the way is
this inflexible paradigm

1662
01:21:57,740 --> 01:22:03,890
of fixed time control with a
fixed cycle, long fixed cycles.

1663
01:22:03,890 --> 01:22:06,605
Like Jan was saying, the
long cycles are killer.

1664
01:22:06,605 --> 01:22:10,190
If you have short cycles,
the delay won't be too much.

1665
01:22:14,320 --> 01:22:19,810
So what Europe has done
with transit priority

1666
01:22:19,810 --> 01:22:20,586
is just amazing.

1667
01:22:20,586 --> 01:22:22,210
Some of the things
that I saw there, it

1668
01:22:22,210 --> 01:22:25,390
just blew my mind
how they're just

1669
01:22:25,390 --> 01:22:26,770
giving priority to transit.

1670
01:22:26,770 --> 01:22:27,436
They just do it.

1671
01:22:27,436 --> 01:22:28,255
They just do it.

1672
01:22:28,255 --> 01:22:30,150
They just do it.

1673
01:22:30,150 --> 01:22:32,680
There was an intersection
in The Hague,

1674
01:22:32,680 --> 01:22:36,460
right near Delft, where a
tram line was intersecting

1675
01:22:36,460 --> 01:22:38,050
the main ring road.

1676
01:22:38,050 --> 01:22:42,710
Lots of traffic and
big traffic jams.

1677
01:22:42,710 --> 01:22:45,740
And my friends are telling me,
oh yeah, big traffic jams here.

1678
01:22:45,740 --> 01:22:46,550
How come?

1679
01:22:46,550 --> 01:22:49,100
Well because we have to
give the tram priority.

1680
01:22:49,100 --> 01:22:53,040
It's like you just have to.

1681
01:22:53,040 --> 01:22:57,080
You drink coffee in the morning,
and you give the tram priority.

1682
01:22:57,080 --> 01:22:59,990
Who would ever think of making
the tram wait at a red light?

1683
01:22:59,990 --> 01:23:00,800
No!

1684
01:23:00,800 --> 01:23:02,660
You have to give
the tram priority.

1685
01:23:02,660 --> 01:23:04,010
And there are lots of trams.

1686
01:23:04,010 --> 01:23:06,480
And it's causing
a big traffic jam.

1687
01:23:06,480 --> 01:23:08,390
So what's the solution?

1688
01:23:08,390 --> 01:23:12,290
Spend a lot of money, grade
separation, and now the tram

1689
01:23:12,290 --> 01:23:14,434
has absolutely zero delay.

1690
01:23:14,434 --> 01:23:16,850
And the cars go underneath,
and they have no delay either,

1691
01:23:16,850 --> 01:23:18,170
and everybody's happy.

1692
01:23:18,170 --> 01:23:21,670
But it started because
of this attitude

1693
01:23:21,670 --> 01:23:26,620
that we just give priority to
our important transit lines.

1694
01:23:26,620 --> 01:23:31,240
So if we have that
attitude, we can

1695
01:23:31,240 --> 01:23:34,800
do it a lot better
than what we're doing.