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NEEMA NASSIR: So good afternoon, everyone.
Today, we are going to continue the discussion regarding
short-range planning for transit agencies.
And if you do not have the set of slides,
the handout from last week, there are extra copies here.
Please, you can take from here.
OK.
Thanks.
OK.
So last week we--
last Thursday, we talked about the basic concepts
in the practice of short-range transit planning,
the level of service guidelines and performance measures that
could actually be defined and used
for the practice, particularly related
to excess distances, services span, maximum load,
convenience, and comfort measures.
Today, we will talk a little bit more
about guidelines and standards related to reliability,
and then we will talk about some of the useful performance
measures that could be defined and measured
for transit service.
And then we will talk about the actual procedure
of short-range planning for some of the agencies from which we
have some examples.
And then we will talk about some of the caveats that
could actually be identified for those.
So let's start with guidelines and with the standards related
to reliability first.
So in terms of reliability, as we briefly discussed last week,
most agencies have formal procedures
for monitoring service delivery focusing on time performance.
The on-time performance is usually
considered to be zero minutes early and up to five minutes
late.
As we discussed, early arrivals is not considered on-time.
That could be because early departures basically are not
considered on-time because early departures could actually
have a more negative impact on travel time.
And the other possible reason is that it's probably
early departures are easier to avoid.
When you compare later arrivals or later departures,
possible reasons that could actually
contribute to a late arrival could
be the vehicle getting stuck in traffic, congestion,
or due to high load and high dwell times, which is usually
difficult to avoid.
But when it comes to early arrivals and early departures,
the driver could actually slow down in the upstream segments
to make sure that the arrival is kind of on time.
So about 2/3 of agencies-- there are different thresholds
that are defined in terms of acceptable thresholds
for the percentage of arrivals within this tolerance interval
from zero to five minutes late.
However, the usual practice is that about 2/3 of agencies
report on rush hour, on-time performances of 90% and above.
But in practice, this threshold ranges between 80%, 85%,
up to 90%, 98%, depending on the mode of the service
and depending on the situation, how the congestion level is,
how the load in the network is, if there is right of way,
like separated right of way for that transit service or not.
So it is written somehow as specific to the system,
but 90% is basically the threshold that 2/3 of agencies
basically accept.
Most agencies also keep track and keep route level
information on passenger complaints
that could relate to on-time or late arrivals.
It could relate also to denial to board
or to the crowding situation.
They would also keep track and keep information
on missed trips and accidents and interruptions
and disruptions, basically.
So when it comes to reliability, there
is a need to explain this.
I briefly mentioned this last week,
that the services, the transit service
is basically classified into two types.
One is walk-up service, which is related to higher frequency
service that is usually schedule-free
and/or headway-based.
Typically with a service that is with headway
less than 10 minutes or some say less than 15 minutes,
it's considered to be walk-up service.
For example, the T service in the central area of Boston
would be considered a walk-up service.
BRT systems are also, some of them
are schedule-free and could be considered walk-up
or basically, headway-based.
Performance measures that are related
to reliability for walk-up service is based on headway,
and it basically measures the regularity of headways.
As opposed to service, which is scheduled that's basically
based on published timetables and published schedule
and delivered based on that, basically that's
the service that is usually for longer headway.
Headway is longer than 10 minutes, 10, 15 minutes.
And the performance measure related to this service
is usually being done or being measured
based on punctuality of service, being late or early.
So again, a trip is considered on time
at each time point along the route
and on the performance window, basically.
So usually, transit agencies, for each route
they define certain time points, which
could be major stops or stations but usually, they
are less frequent.
I mean every three or four stops,
there could be one time point that you
measure the on-time arrivals and on-time departures from there.
You may have noticed, if you're on a certain bus,
this is my personal experience, when I
lived in Brisbane in Australia.
There were some routes that at some time when
you see that the bus is early, the driver could actually
really slow down before certain points,
and you could tell where exactly the time point is
that the driver is trying to basically make
an on-time arrival to those time points.
So arrivals are measured at these time
points along the route.
Right.
So what are the actual standards and actual tolerance
or thresholds that agencies consider for service
reliability measures?
One example is here from MBTA.
MBTA, actually for walk-up service,
which is the case for most of the T service,
it allows basically actual headway
of up to 1.5 times the scheduled headway
at origins and at time points.
And then at destinations, it also
defines another measure that deals with the schedule's
running time.
So basically, there are two hooks
that it kind of measures the service based on those.
One is the regularity of service.
It doesn't allow or it wants to measure cases
where headway is longer than expected, like 1.5 times
the scheduled headway.
And the other constraint is that the actual running time
is between 0.8 and 1.2 of the scheduled running time.
So when it comes to actual headway,
you can see that there is no lower bound
to the actual headway.
Does anyone have any comments why there is no actual lower
bound here?
Yeah, please.
AUDIENCE: Lower than scheduled headway just means
that there's more service.
And if that leaves a gap somewhere else,
then that would be record-- that would
count for over the schedule.
NEEMA NASSIR: Right.
Yeah.
Given that the number of trips are constant during the day,
if you guarantee that there is a maximum headway, then
on the other hand, you can kind of
guarantee that headway is not too short there.
However, when it comes to scheduled service,
then there is constraints on early and late departures,
basically.
So at origins, what MBTA considers, at origin terminus,
considers on-time departures between zero and three
minutes, zero minutes early and three minutes late.
And then at time points, it allows up
to seven minutes late.
Does anyone have any comments about the difference?
Why does it allow less late departures
at the origin terminus?
AUDIENCE: Give us control at the intermediary terminus
[INAUDIBLE] at the terminal.
NEEMA NASSIR: Yeah.
That could be the case.
or to put it the other way, transit agencies,
when they schedule these trips and they schedule
these vehicles, they allow a recovery time
between the end of one trip and the beginning of the next trip.
And that actually is there to kind
of help with punctuality of service,
and therefore, it does allow less tolerance on delay
at the beginning.
But when it goes along the route, when
bus goes along the route, it kind of
gets out of control as you mentioned.
There are not really good ways and good leverages
to allow buffer to the running time.
And then at the destination, it's basically,
MBTA allows up to three minutes early
and five minutes late it should be obvious
why it allows early arrivals to destination because it's
the last stop, and we don't need to worry about arriving early
to the final destination.
At the route level, there is one other guideline
that, at the route level, 75% of time points must be on time.
So although for the overall system,
the threshold here was in the range of 90% or 95%,
or between 80%, 85%, and 95%.
But at route level, when you're looking
at the on-time arrivals, it has to be larger
than 75% of the time.
So what will happen if it doesn't--
a certain route doesn't meet this standard?
Is there any thoughts?
Oh, please.
AUDIENCE: You could shift the schedule for that segment
and republish it and add extra--
NEEMA NASSIR: Yeah.
So you can increase, basically, the running time
and make sure that you adjust the schedule in a way that
can be delivered punctually.
So that's what's explained in this slide.
So if you observe in some of the routes the performance in terms
of punctuality is poor, then you can take a look
at the historical data and historical performances
in terms of running time, revise the running time
from terminus to terminus and that will actually,
you can basically revise that to be a mean of this distribution,
assuming that the travel times, the running times
are distributed normally.
And go ahead, please.
AUDIENCE: I mean, if it's only a 5% probability
that this will happen but it happens actually
a lot more than that.
It's probably a result of another factor,
like drivers or vehicles or traffic or [INAUDIBLE]
constructions [INAUDIBLE].
NEEMA NASSIR: Well, that's a good point, yeah.
So there may be, for example, you
know when there is shared right of way with background traffic,
there's a lot of indeterminacy in terms of travel time,
especially if the roadway is congested,
and that could be one possible result for unreliability
of running time.
One possible thing that could be done is like dedicated lanes
to the transit and kind of trying
to improve the performance and match the schedule.
So that could be one other way.
But what I mentioned was that if this is the last thing that we
can do and that we cannot basically improve
the reliability of arrivals, we may actually allow a little bit
of buffer to the travel time.
And that's not only by extending the running time to a job
that we can observe, but also, you
can adjust the recovery time between end
of one trip to the next trip to the chosen amount that
makes sure that a certain confidence can actually
be gained in terms of on-time performance of next trip.
In terms of the actual objective that TransLink
has in place for reliability, again depending
on different modes, TransLink defines
different acceptance thresholds for given on-time definitions.
And on-time definitions could actually
vary as well as a level of compliance or the acceptance
threshold.
So is there any questions about this?
Any comments?
So there are some more detail measures and event
measures for transit service.
It comes to variables that are related to transit service
supply and demand side.
Quantities actually can be classified
into three different groups, the quantities that
are related to the service input,
quantities related to service output,
and quantities related to service consumption.
So service input is basically the resources
that the transit agency is using to produce the service.
Service output is basically measuring the produced service.
And service consumption is how this service
is being consumed and being appreciated and being
used by the public.
So different measures can be defined
to measure the performance of transit system
based on these quantities.
For example, you can look at only the vertices
of this triangle, like what is the amount of labor, including
drivers and maintenance?
What is the capital cost of the fleet and infrastructure?
What is the fuel consumption in the system?
Or, on the other hand, you can look at the service outputs.
It would be like a measure of the service
in terms of how much service the system actually
is producing in terms of vehicle hours or revenue hours, vehicle
miles or revenue hours, capacity miles and service reliability.
And then consumption of service, that
is dealing with number of passengers,
passenger miles, operating revenue, and operating safety.
But you can go one level up with playing with these measures
and compute, for example, the ratios of these quantities.
So each one of these edges basically
are dealing with the ratio of one quantity
at one vertex as opposed to over the quantity of the other one.
For example, what we are basically--
efficiency measures are basically
dealing with how we are doing in terms
of producing service as given our available resources
or the consumed resources.
The service effectiveness basically
deals with how we are doing in terms of giving service
to public, moving public and producing mobility
in the network over the service that we
produce, how our service is appreciated and used
and utilized.
For example, a service that is poorly designed, for example,
like every five minute trips overnight
from a suburb to another suburb, it's a service,
and it has produced vehicle hours and vehicle miles.
It has consumed resources.
However, it may not be appreciated
because it's poorly designed.
So that's the kind of the role of measures
that are related to service effectiveness
to take care of quality of design and quality of service,
basically.
So and one other comment about this triangle
is that the cost efficiency measures
kind of dealing with the quality of the planning
on the operational side, operational planning.
How the optimization and how the tactical decisions
are made in terms of producing the most service out
of the existing resources.
On the other hand, the decisions that
are related to service planning could actually
use measures that are related to service effectiveness.
So in terms of alternative measures,
like benefit and cost measures that could be defined and used
for short-range transit planning--
before we go into discussion of benefits and cost
for transit system, there is one thing that I need to mention.
What's happening in transit system
is that they are usually not run, as you know, for profit
and that's probably one of the main differences
between the business model of a transit system as compared
to other regular businesses, where they make decisions
based on profit and based on the revenue over or benefit of cost
or better benefit over cost.
What happens in transit agencies is
that it can be thought as a type of benefit over cost analysis
but the cost and benefit is a little bit different.
The benefit is dealing with the public service and the amount
of consumer surplus or the social welfare
that you can produce, the mobility that you can produce.
On the other hand, the cost could actually
include the operating cost and also could include the revenue.
It basically can be defined as operating cost minus revenue.
So when it comes to the financial unit of benefit
and cost, the financial unit includes both the cost
and revenue.
And then when it comes to benefit,
what's usually being used as a measure of benefit
is the service that is being delivered
in terms of the social welfare measure
or the mobility that actually is produced in the network.
So once we discuss some of these alternative measures,
it may be a little more clear.
So one of the measures that could
be defined and really easy probably to define and measure
is the revenue.
Like, what's the fare box revenue?
What's the total?
The advantage that this measure would have
is that it's very relevant to financial concerns.
It actually, another advantage that it has
is that it's related to willingness to pay
and it could be used as a proxy of quality of service.
However, the disadvantage that could be mentioned for revenue
as a benefit measure is that it discounts
value of reduced fare trips, discounted trips, concession
trips.
And it also has the disadvantage that it favors higher income
passengers.
So if we want to look a little bit more
closely at the nature of transit service
and what should be considered as a benefit measure,
we need to look at the mobility and try
to measure the mobility that has been produced for the citizen,
for the people living in the network.
So we can count the number of passengers
who have used the system and the advantage of this
is that it reflects the number of people who benefit
and it basically values each passenger equally.
However, the shortcoming of counting
only the number of passengers is that it kind of
doesn't reflect trip length.
Not reflecting trip length basically kind of
ignores an important component in mobility, which deals
with access to opportunities.
Which the access to opportunities definitely cannot
decrease with the opportunities for mobility.
And then the other shortcoming is
that it basically reflects on link trips
and not journeys or link trips.
So you basically double count passengers
who are making transfers, although they
may be traveling to one destination
and there's only one opportunity at one destination
or that will be actually one activity happening
at the destination.
So one way to improve this is to measure passenger miles
as a better proxy of mobility in the network.
It has the advantage that it weights longer trips more
and it's the best reflection of benefits related to mobility.
Sorry about this.
However, it's hardest to measure.
Does anyone have any idea, comments about why it's hardest
to measure?
Why is passenger miles in the network hardest to measure?
AUDIENCE: A lot of systems don't have an exit.
They only have an entrance stile.
NEEMA NASSIR: Exactly.
So considering that we're using the data for passenger,
like from fare card systems, many systems
do not have the requirements of tapping
when you're exiting the system.
So that's something that is missing.
So it requires some sort of inference
of highlighting our exit locations to be able to measure
the length of trip.
However, and the other disadvantage
is that it could find favor higher income passengers.
So any comments about this?
AUDIENCE: That assumes the high-income passengers,
that assumes higher income people travel further.
It's not necessarily the case.
NEEMA NASSIR: Not necessarily the case
but in systems where you have distance-based fare structure,
and when you basically have the entrance and exits recorded
and you charge people by the length or number of zones
that they have traveled, that could be actually
somehow favoring higher income passengers
because it is reasonable to assume that higher income
people are less sensitive to the fare
and so their decisions are basically
kind of regardless of fare.
So any comments?
OK.
So then on the cost side, the measures that
are dealing with cost, the net cost
is basically cost of resources that
are used to generate the service minus the revenue.
And it's usually most directly constrained
because that's exactly the amount of money
that you need to secure for the service.
The budget actually goes directly to the net cost.
So that's the advantage.
However, the disadvantage is that it's hardest to estimate.
Any comments about why it could be hardest to estimate as
compared to cost?
At least for designs, for the service that is not already
in place, if you need to estimate the revenue
and deduct that from cost to generate net cost,
it would be a challenging thing to do,
to come up with estimates of demand and predict the revenue.
So that could be one of the shortcomings
of net cost for designs.
However, it may not be that difficult when
we are dealing with the existing service
because revenue is basically already recorded
by the fare box system.
And then cost could be another measure less directly
constrained because actually, we need to combine that
with the revenue to realize what's
the net cost of the system?
Again, it could be hard to estimate
but probably not as hard when we compare it with net cost.
Go ahead.
AUDIENCE: What is net cost?
NEEMA NASSIR: Net cost is basically cost of operation
minus the revenue from fares.
And the reason that it's tricky to measure
is that the revenue side is probably a little difficult
to predict.
So the next measure of cost could be vehicle miles.
That basically deals with the service that is produced.
It's easy to measure because you know number
of trips that are delivered to the system, and length of trips
are known.
So vehicle miles is probably the easiest measure to compute.
But the disadvantage is that they only
reflect 3% of the cost and that's probably
the part that is correlated with fuel and with depreciation
of the vehicles and with maintenance.
And then it also penalizes fast service,
not [AUDIO OUT] traveled fast and on time
as opposed to the model that is basically
delivered in congestion and with long delays.
Another measure that is probably a little bit more
closely reflecting our cost is the vehicle hours.
And the vehicle miles and vehicle hours
are basically the revenue miles and the revenue hours.
What I mean by revenue, that's basically the miles
that these buses and these vehicles
have been in service from the start of their trip
to the end of the trip.
There may be some trips, like dead-ending trips,
that the vehicle can should go empty from one
location to another location to the next trip,
and those miles and those vehicle hours
are not counted here.
So vehicle hours basically, again, are easy to measure.
And the other advantage is that it's related to more than 50%
of bus costs.
It basically correlates with the fuel consumption
and with driving and operating cost.
So one of the cost effectiveness measures
that MBTA uses for their system and for their decision making
is basically net cost per each passenger that
is using the system.
And then they usually define this on a route basis.
So the index I here could be net cost per passenger
for each route, and then it shouldn't exceed three times
the system-wide net cost per passenger.
So this is basically going back to the triangle that we had.
This is one of the measures that is dealing with resources that
are used to the number of passengers
that are using the service, regardless
of what the service was.
So in terms of issues in setting up a short-range transit
planning process, this slide mentions some of these issues,
starting with the roll-off budget
constraints in the process this could actually
be related to before budget is set and after budget is set.
Before budget is set, there is some indeterminacy
in measuring the net cost and basically
the budget that is requested in the proposal for a new service
or for a change in the service.
What's similar to any other proposal that is usually done
is that you try to find the minimum possible budget
that you're requesting for what you're trying to deliver
and that could be a challenging task.
And then after the budget is set,
given all the indeterminacy that was involved in predicting
the budget, then it's the issue of optimizing the resources
and optimizing the budget to deliver and to gain the most
out of the existing resources.
The other issue with--
AUDIENCE: So in this part of the process,
I wonder if it should be advisable to leave
a margin of maneuver in respect to budget constraints normally
you would have, even if you go for the minimum possible to get
85%, 80%, out of that, for political reasons
or whatever reason there is.
NEEMA NASSIR: Right.
So that could actually make the situation a little easier
for people who are involved in planning
and for the actual plans, right?
So what Ricardo is mentioning is there may be
some buffers or some internal--
some buffers in the budget and some flexibility
in the budget that could actually
be allowed when you're requesting the budget
and when you're delivering the budget,
delivering the service that could actually
take care of some of the indeterminacy that
is involved in the prediction of the budget
and prediction of the costs.
So the next, possibly the next issue
that is involved in the traditional or the existing
practice for short-range transit planning
is that we kind of have a set of standards and constraints
that gives us lower bounds on some of the service measures.
However, these constraints only give us
an idea of what's the feasible solution space.
It doesn't really tell us what's the optimal design
and how you can basically optimize
the allocation of resources to improve the ridership.
And that could actually involve some
of the art of the designers and the art of people
who are involved in identifying opportunities
within the standards and within the constraints and guidelines
to address the situation and to gain the most
out of the allocated resources.
Then again, when it comes to design of service,
there is also this issue between the existing
service and proposals and plans for additional service.
As I mentioned last week, the design of service
is never from scratch.
There is always something there for good reasons
and you may want to predict the existing service
as much as possible because people
are relying on the service.
They probably have formed their travel habits and travel
attitudes based on the existing service.
So changing these services probably
need to be really careful and thoughtful, basically.
However, when it comes to addition of new service,
we may want to make sure that the new service
kind of supports the existing service effectively
and with all the overlaps and all the misconnections
are identified in advance and taken care of.
Issue that we will eventually talk about it later
in another slide is that some of existing practice
is dealing with short-range transit planning decisions
dealing poorly performing routes.
But the optimal design is not always
dealing with changing the ones that are only poor,
the only ones that are poorly performing.
There may be some changes that you
can do to well-performing routes to improve the overall system
performance and the network level performance.
So is there any questions so far?
How am I doing on time?
OK.
AUDIENCE: Professor Nassir, does the cost effectiveness standard
work if they can't compare the cost
effectiveness of [INAUDIBLE]?
NEEMA NASSIR: My sense is that it
has to be in a modus specific, but yeah,
but I can take that and--
Yeah.
It makes more sense to be, yeah, because you probably cannot
compare the effectiveness of a bus versus a train in terms
of operating costs at least, right?
So this is the standard process of decision
making when it comes to new projects and new proposals,
service proposals, and changes to the existing service
in Toronto Transit Commission.
This gives you an overview of different tasks
that are basically done to start with a set of proposals
and to make the decision on which ones to be implemented
and so on and so forth.
So if you look at the column on the right,
it basically includes the decision--
it deals mostly with the decision making
on the new service proposals.
First, you get some requests from municipalities
and some suggestions from the staff
about new service proposals.
Then, if these proposals are passing your system guidelines,
then there would be two possibilities.
If they are minor costs, they'd go directly to recommendation.
And if they are major costs, then you
need to do a benefit cost analysis,
and that basically includes estimation
of ridership and estimation of costs and benefits.
And then, once you have a better sense of benefits and costs
and benefit/cost measures of the project,
then there will be a comparative evaluation
of alternative designs and alternative proposals.
At this stage, there will be another input
from changes to the existing system that
comes into the comparative evaluation, which we will
get to that branch in a minute.
After these projects get to the recommendation level,
the staff makes a recommendation to the board,
and then there will be a review and decision
about acceptance or rejections of some of these proposals.
And then there will be an implementation
of the successful proposals.
And then there will be a probationary time
to implement the successful proposals and then to,
after six months, it will get back to the recommender team
to see if it would pass the probationary period.
On the other hand, there is a set
of proposals that are made to make changes to the existing
service and that basically comes from two main streams--
one is a continuous monitoring of ridership and loads
and the other one is the annual route efficiency review.
And from this, then the staff actually
identify service changes and assess the impacts
on passengers.
If the impacts are minor, it goes directly
and it becomes implemented.
If impacts are major, then these changes
become into a form of a proposal and comes
to the stream of comparative analysis
that would be actually compared with new service proposals
and follow the same procedure with that.
OK.
Any questions about this?
We'll actually get to the main two streams
on changes to the existing service
in the second next slide right now.
So the first slide is dealing with basically
the continuous monitoring of the system
that Transit Authority or transit agency staff
regularly do.
It's basically, the input into this kind of process
involves ridership counts, regular ridership counts,
customer communication, customer complaint records,
some observations from staff in terms
of the performance of these routes
and for possible adjustments that
could be done and then from operations report.
Then there will be a comparison of ridership to load standards.
What we basically discussed last week
in terms of level of service measures related
to maximum load will actually be tested for all the routes.
And then depending on the situation,
if there is available vehicles and budgets, then the staff
actually making their recommendations of changing
the service, if there is availability of vehicle
and budget, there will be improvement in the service
and increase in the service level.
And then it will be reviewed for recommendation, staff approval,
and implementation, and this is a closed loop that is usually
done on a regular basis.
Then there is another process related
to the existing service that deals
with yearly review of the routes in terms of route efficiency
review.
And basically, you kind of consider a route
from a cost and benefit perspective.
And on the left, you can see new riding counts or yearly riding
counts that's actually are collected from the study year.
And then that goes complemented with the record
of complaints and customer satisfaction
reports and service regularity.
And it will be combined with the financial performance
and basically the measure of costs
that are spent to each route.
And then it comes to this joint here with reviewing
the structure of the route.
Some of these routes may be routes
with branches which actually makes the analysis a little bit
more difficult, especially design
of branching and alignment of branching, making sure
that the frequency and the load profiles and maximum loads
are actually satisfying the standards
before and after the joints.
Because as you may have already thought about,
some of-- so, for example, say Green Line here in Boston,
in the part that is--
for example, where you have higher demand
in the central area, one of the effective techniques
in design of routes is to join some of these routes
into one service to avoid additional transfers
and to produce connectivity to the central area
without need of a transfer here.
However what it actually causes is
that the demand that you're collecting from lower density
suburbs are basically based on given frequencies here.
And you set these frequency based on these demands.
But when it comes to the merge points,
the frequency will be the combined frequency
and the demand, kind of crowded situation
will be the combined situation.
So you need to make sure that all these standards and all
the guidelines are holding for all these branches
at the same time.
OK.
And then after that, let me try to clarify this a little bit.
For example, considering the--
similar to the example that we made
last week related to two suburbs that are actually
using the transit service.
So let's say suburb one, suburb two, and this is downtown area.
If the existing service is a direct line between suburb one
to destination and passengers from suburb two
basically walk to this stop to get to destination,
then assume that the new proposal of service
is basically adding one detour here to serve this.
Try to clarify this a little bit.
For example, considering similar to the example
that we made last week related to two suburbs that
are actually using the transit service in the--
so let's say suburb one, suburb two, and this is downtown area.
If the existing service is a direct line between suburb one
to destination and passengers from suburb two
basically walk to this stop to get to destination,
then assume that the new proposal of service
is basically adding one detour here to serve this suburb
two on the way to destination, then what needs to be done
is that we need to make sure that the total generalized cost
that is computed for all the passengers from suburb
one and suburb two to destination
would be reduced after the introduction of this detour.
And then how do we compute the total generalized cost
that is experienced by the passengers?
There are some equivalent values that are usually used.
For example, for every vehicle travel time,
you assume, one in vehicle travel minute.
And then for every minute of waiting time,
you assume 1.5 or so.
For every minute of walking time that is required,
you consider two minutes of in-vehicle time.
That's the case for, for example,
when you want to measure the cost of walking from this area
to the stop.
And then the cost of each transfer
is considered to be 10 minutes, equivalent to 10 minutes.
Is there any questions about this?
AUDIENCE: So from the local suburb [INAUDIBLE] so in case
there would be [INAUDIBLE] However,
it may just be the fact that [INAUDIBLE]..
NEEMA NASSIR: Right.
If the service can attract latent demand--
so the question was that this condition does not
account for latent demand, and it kind of
assumes that the demand is constant between the two
scenarios.
So my impression is that whenever
there is latent demand, that could actually
be considered an advantage.
So you can safely assume with the existing level of demand
if this change or if this new service can
reduce the total system cost?
But I do not know how they exactly
implement this when it comes to demand prediction.
OK.
So any other questions about this?
You may ask where does these numbers come from?
I mean, these coefficients, how do we get these coefficients?
They may make sense.
At least, to me, actually, they're
kind of consistent with the way I perceive the cost of travel
in different components of trips, in vehicle time,
waiting time.
Go ahead.
AUDIENCE: Why is the transfer worth more than 10?
NEEMA NASSIR: That's 10 minutes considered
for one required transfer.
So for example, that's the case where
you have direct access between origin and destination
versus where you need to make at least one transfer to get
to destination.
So the way these coefficients are quantified or understood
is that if you look at the choices
people make in terms of paths that they choose,
given their available path alternatives,
and you can basically calibrate these coefficients based
on the assumption that passengers
try to maximize their utility or minimize
their generalized cost.
There is techniques involving the theory of utility
maximization that is usually used
in practice to look at the actual observed path
choices the passengers are making
and quantify these coefficients.
AUDIENCE: So what if you maximize--
I mean, for that to result in benefit for customers overall,
you would have to increase, for example,
like headways or frequencies from part of the trip,
but then go back to previous frequency levels?
NEEMA NASSIR: You mean, in the merging?
AUDIENCE: Here, as part of the transfers.
It's only way to maximize the benefit for customers.
NEEMA NASSIR: Right.
So the scenario that I tried to explain here
was removing this route and adding
this layout for the route and replacing it
with this alternative.
So you can keep the same frequency before and after
and the waiting time could be kind of the same.
Or you can alternatively add additional routes
and improve the frequency for other parts of the system
but make sure that you're serving the demand
on the distant suburb.
AUDIENCE: How do you compensate the path right here?
NEEMA NASSIR: This one, right?
This part?
AUDIENCE: Yeah, because they're traveling a longer route.
NEEMA NASSIR: Yeah.
They basically-- the in-vehicle time for these people
will be increased.
So this is the measure like the--
after you implement this change, if you want to and analyze
the scenario, the in-vehicle time for traveling from--
it's usually IVT for S1 to D for after will be greater
than IVT for S1 to D, right?
So in-vehicle time will be increased.
However, what's going to change for passengers
who are traveling from S2 to D, the walking distance
is going to decrease, which has a coefficient of two.
The in-vehicle time may increase somehow
because they are boarding now at this point,
but depending on what frequencies you're designing,
you can compute the waiting time and put that into consideration
and into computations.
So how are we doing on time?
OK.
So Toronto financial standards and comparisons--
basically, service change proposals
are evaluated according to customers gained or lost
per dollar spent or saved.
Again, the benefit that is imagined for transit
is in terms of the number of customers,
the number of passengers that are added and are
using and benefiting from the service.
And the cost side is basically the net cost,
like the operating cost minus the revenue.
And Toronto applies this for new service proposals
and possible reduction to the service and to fare changes.
Again, the financial unit actually
that goes into these computations
is the net cost, operating cost minus the revenue.
And the threshold that is used by Toronto
is 0.23 as the standard threshold,
that's 0.23 passengers per dollar spent.
So for each dollar that you're spending
on the operation minus the revenue,
you need to guarantee at least point 0.23 passengers are
basically getting served.
AUDIENCE: That's operating dollars and passengers.
It's not a capital expense.
It's operating.
NEEMA NASSIR: It's operating.
Yeah, I think it's operating cost minus the revenue,
probably, right.
AUDIENCE: Yeah, OK.
NEEMA NASSIR: Right.
And then services that are operating below this level,
we actually get kind of reviewed in the annual yearly review
process.
Again, in terms of service change process,
major service changes are evaluated twice per year.
They're basically ranked in the comparative analysis
and based on their performance and based on productivity
of the existing service.
There is a board in the Transit Agency
that makes these decisions.
Usually, they invite people from metropolitan transportation
planning agencies too or higher level governmental agencies.
So these boards basically review the recommendations
from the staff and make decisions
based on their merits.
The guiding principles for TransLink
for Vancouver in service optimization program,
is to maintain basic service for transit-dependent customers,
like what we discussed about the existing service
and how passengers may actually be dependent.
And we need to be careful when we
want to remove some of the existing service
and maintain service that are strategic for network
connectivity.
Sometimes it becomes a little tricky
when we look at the routes individually and do not
consider their role and their functionality
in the performance at the network level.
So the guiding principles of TransLink
kind of enforce this concentration.
And then minimize service reductions in area
with no transit alternatives, supporting growing market
where productivity is improving, reinvest in service
to generate higher revenue ridership,
and reinvest in service that supports long-term goals
and objectives of TransLink.
So let's open a discussion now for a few minutes in terms
of possible critiques and possible caveats
of the existing practice for short-range planning.
Let's start-- does anyone have any comments or any thoughts
about the existing caveats or critiques yet?
AUDIENCE: Slide 36.
NEEMA NASSIR: Yeah, it is actually.
AUDIENCE: Where it says the TTC value is, the financial impact
of service changes.
Any service change proposal is evaluated
according to customers gained or lost per dollar spent or saved.
Does not mean that they could eliminate
any stops, for example, and not lose any customers?
They'd just make those customers walk further
and make service less convenient for them,
that that would be a sound decision according
to these criteria?
NEEMA NASSIR: So yeah.
So do you mean, if you're making some changes that reduces
the actual number of customers--
AUDIENCE: Say they make a change and they don't lose customers
but service is worse for customers.
The customers have no other options,
so they continue using the service, even
thought it's slightly worse.
NEEMA NASSIR: So yeah, that's a good point.
That's a good point.
So probably the important caveats
is that many of these guidelines and standards
are not from the passenger's perspective.
So passenger's perspective performance measures
and passenger's perspective perceptions
of the quality of service is something
that probably should be incorporated
in some of these measures.
AUDIENCE: Isn't it some of the checks and balances in place
because it's relatively easy in services
neutral users of these services lean on it
and some people have to walk further.
So that in itself would lead to a reduction in the number
of people who take the route.
So for example, from suburb S1, the number of people
who [INAUDIBLE] So analysis at route level, because then
it might actually go in favor of the agency.
NEEMA NASSIR: So exactly.
So analysis at the network level should
be something that probably better captured
by these guidelines.
And one of the other things that is not actually included here
is the actual objective of transit agency, which
is improvement and increase of the ridership, which
is not explicitly tied to any of the existing guidelines.
That's something that could be identified thinking of it
as an optimization problem as an optimal or objective function
to be optimized over the solution of space, which
is the guidelines, existing guidelines
and standards in the service.
So what this guideline that we discussed
here is just the bound on what is acceptable
and what's not acceptable.
But the fact that is this going to be beneficial to the system
or not?
That's something that requires better analysis of the plan
basically.
So any others?
OK.
AUDIENCE: Comment on just one thing.
Is this less for the short term service planning
and the problem with short-term planning
often a lot of the demand and [INAUDIBLE]
will be contemplate.
Whenever you do major additions, extensions,
or you have a major budget crisis
and it's a cut off service, that would not
be considered entirely a short-term thing
but more of a bigger impact.
So the study would be required with demand more.
NEEMA NASSIR: Correct.
Exactly.
OK so in the last slide there is a list of possible caveats
that are mentioned here.
Couple of those we already discussed.
Focus of the existing practice is on poorly-performing routes,
whereas it does not necessarily have
to be a poorly-performing route that has the potential
to be improved to improve the performance of the system.
There is data limitation both on type and quality.
We observed that in many of the measurements
and in many of the decision making,
there is lots of uncertainty that
is related to quality of data and limitations of data.
So hopefully, with the new generations
of passively-collected data that are nowadays introduced,
there will be improvement in the existing practice
to take advantage of that data and improve the planning
process.
Again, measures not always closely tied to objectives.
That's something that is relevant to what
Adishak mentioned in terms of some of these measures
are basically just constraints and lower bound
and they're not necessarily tied to the objective, which
is improvement of mobility and improvement, increase
of ridership.
And then focus on individual routes
may actually not be ideal because kind of it
ignores the network level functionality of routes.
So any questions about this?
Any additional comments in terms of--
right.
OK.
Yeah, please.
AUDIENCE: So the idea of utility is not always something
that someone actually calculates for when
they're considering these simulations
or calculations or changes.
It's kind of theoretical.
If we do this then it will affect us
but there isn't necessarily a quantitative way.
NEEMA NASSIR: Right.
The utility itself is a random and unknown quantity, right?
There's a random component to it.
But the marginal rate of substitutions
of these coefficients related to different components,
that's something that can be quantified.
For example, what is the disutility
of waiting time as compared to the disutility
of in-vehicle time.
So that's a way kind of have a sense of the generalized cost.
AUDIENCE: Couldn't you also use a dollar proxy
to say that the economy is stimulated in x, y, and z?
Is that another way of looking at it?
NEEMA NASSIR: I think the--
yeah, I'm not sure about--
AUDIENCE: It's typically used for capital investments.
All these people that are looking
for short-term funds, things like environmental impacts
and economic welfare at a large scale are equally the methods.
You are considering a minor extension or increase
in service with the same alignment.
So you're probably not going to do a fully [INAUDIBLE]
gradual marginal change.
But in a bigger context then, yes, you would have,
a four-step model and you would look at CO2
and look at many other things.
And one example of that would be the recent example
of London Crossrail, where a lot of the business
case for Crossrail had to do with deliberation and things
like this, not necessarily the time that people were saving.
AUDIENCE: When we say poorly-performing routes,
are we talking only in terms of timing, for example,
or are we also talking about poorly-performing
in terms of financial return of the route?
NEEMA NASSIR: Right.
Right.
AUDIENCE: I'm afraid that for example, if people
talk about financially, certain routes might get closed
for low demand, and then you have the equity problem
that we talked about over there.
NEEMA NASSIR: Right.
Yeah.
So I believe when you're evaluating
the quality of these routes, we can
use all the existing criteria that we mentioned.
For example, the criteria that is related to access,
the criteria that is related to span of the service, access
over time and space, and then measures
that are dealing with the productivity of the route
and the financial aspects.
So my guess is that this is probably
kind of when we're evaluating the routes,
we are taking into account the equity issue
and the access issue and all those sorts of guidelines
that we discussed last week into consideration.