General

Main points of this article:

• In wealthy countries, transit operating cost is mostly the cost of labor.  This is usually around 70% of the total cost of operations. So:
  • Smaller buses are not much cheaper to operate, unless you pay the driver less.
  • Faster service can cost less to operate, because drivers are paid by the hour rather than by distance.

If you’re going to form coherent views about transit, you have to understand what transit service costs to operate.  There are four parts to this cost:

• Time-based costs vary based on how many transit vehicles are operating and for how long.  The dominant time-based cost is the wages and benefits of the driver and any other on-board employees, which we pay for by the hour.
• Distance-based costs vary with the odometer reading of the transit vehicle.  As in cars, most of transit’s maintenance and fuel costs are distance-based.
• Fleet-based costs vary with the number of transit vehicles owned.  Fleet size is based on the number of vehicles needed to run the most intensive part of the service day, typically the commute period which transit planners call the peak.  Fleet size drives some maintenance cost, but it main impact is the cost of the vehicles themselves, and of the facilities needed to store and maintain them.
• Finally, there may be some administrative costs unrelated to any of these, though in fact most administration costs are roughly proportional to the other measures of size.

The mixture of these costs varies, but in the high-wage developed world, you can go far by focusing on just one element: the time-based costs.

It’s All About Labor

Driver labor, and related time-based costs, are the dominant element – often 70% or more — of transit operating budgets in the developed world.

Most transit vehicles require one transit employee on them to operate, whom I’ll call the driver.  This person’s job description varies quite a bit based on the technology and operations style of the service.  Obviously, driving a train is a different job from driving a bus, and you may or may not be interacting with passengers and dealing with fares.  If you’re the employee sitting at the front end of an automated San Francisco Bay Area BART train, you’re not really driving so much as watching for trouble.  Many North American transit agencies prefer to call the on-board employee the operator, but that term is too vague to be useful here.  So regardless of their exact job description, I’ll call a single on-board employee a driver.

For these one-employee-per-vehicle systems, then, we can understand the basics of operating cost by focusing on how drivers need to be working, and for how many hours.  You may sometimes may hear a transit planner say “if we do this, we’ll save a bus.”  What the planner really means, though, is that we’ll save a driver.  In the high-wage developed world, the driver, not the transit vehicle, is the basis of operating cost.

This is the main reason why transit agencies don’t save much money running small buses rather than large ones, as advocates of small buses often assume.  If an agency does talk about small buses as being much cheaper to operate, they’re probably referring to a difference in driver wages.  Often, some mixture of labor contracts and licensing requirements can allow small-bus drivers to be paid less than large-bus drivers.  In that case, the smaller vehicle is cheaper to operate only because of the pay scale, not because of any feature of the vehicle itself.

So how many service hours does it take to run a line?  This is the one equation that we can’t avoid.  Let’s ease into it.

Service Hours = Span x Vehicles (and drivers) Required.

If a line requires five vehicles (with drivers) in service to cycle the line, and it runs for twelve hours, that will be 60 service hours, 5 x 12.  Easy.  But how do know how many vehicles we need?  Here’s the crucial equation:

Vehicles (and drivers) Required = ROUNDUP (Cycle Time / Headway)

Suppose a line takes 20 minutes to run, in service, from one end to the other, including break time for the driver.  That’s 40 minutes round trip, so the cycle time is 40 minutes.  Every 40 minutes, a vehicle has completed a cycle of the line and is ready to start another.

So if we only wanted service once every 40 minutes, or longer, we’d just need one vehicle to drive the line.  That elapsed time between consecutive trips on a line is called the headway, and it’s the main measure of frequency.  (Remember that high frequency means a low headway.)

Now suppose we want service to come at a 10-minute headway – that is, service every 10 minutes.  We’d need four vehicles and drivers to drive the 40-minute cycle.  Do you want service every 5 minutes?   That will be eight vehicles, and drivers.  If you double the frequency (by halving the headway) you’ve doubled the operating cost.

Lumpiness

Now, suppose we want service on our 40-minute cycle to come every 30 minutes.  We’ll need two vehicles and drivers to do that: the cycle time is 40 minutes, the desired headway is 30 minutes and 40/30 rounded up is two.  But in this case, the cost of running a 30-minute frequency is the same as that of running a 20-minute frequency.

In short, transit’s operating cost is lumpy.  You cannot hire a fraction of  driver.  So at low frequencies, you often end up with inefficient patterns due to the relationship between headway and cycle time.  If we run a 20-minute headway on our route that cycles in 40 minutes, we’ll need two vehicles.  If we run a 30-minute headway, we’ll still need two vehicles, which means we’re really paying the drivers for a 60-minute cycle.  In that case, the drivers will have 20 minutes of extra break time every hour.  Drivers may like these shifts, but transit managers don’t.

Lumpiness has important consequences when designing lower-frequency networks, such as local bus routes in low-density suburbs.  In these cases, good planning designs routes to be of a certain length, so that they will run an efficient cycle. If our network of local routes is meant to all run every 30 minutes, for example, we try to design routes that cycle in 29 or 59 minutes, but not 31 or 61.

A small deterioration in speed can cause sudden big changes in operating cost.  If we’re running 30-minute frequencies on a route that cycles in 29 minutes, that will require one vehicle.  But if for some reason the line slows down just a little, so that it now cycles in 31 minutes, we have to add a whole additional vehicle and driver, doubling the cost of running the line.  A mere 7% increase in the cycle time has become a 100% increase in operating cost.  In that case, a planner may try to redesign the route to make it shorter.

Lumpiness is an important reason that route design and scheduling need to be done together – especially in low-frequency networks such as those of small cities, outer suburbs, or in the middle of the night in big cities.  Some transit agencies try to think in separate, rigid, non-repeated steps:  First, planners design the route.  Second, we drive it and establish the running times.  Third, schedulers write the schedules.  Thinking that way makes it impossible to optimize the efficiency of schedules and connections.  The three tasks have to work together, or at least in several cycles of revision so that planners can revise their structures in light of the apparent running times.

The Elements of Cycle Time

Finally, let’s take cycle time apart.  It has three parts:

• The length of the line, in km or miles, round trip.
• The average speed at which the service can operate, including passenger stops.  This speed, times the length of the line, is the running time.
• Added factors called layover and recovery.  Technically, layover means driver break time, which is usually specified in labor agreements, while recovery means time added to the schedule so that a late vehicle has a chance to catch up to the schedule.  In practice, these two kinds of time are usually added together as one factor.  For example, an agency policy or labor contract might require adding 10% to running time, for layover and recovery, to generate the cycle time.

The One Equation

So here’s how it all fits together.  Operating cost varies mostly with service hours (technically called revenue hours in North America), and these hours are figured like this (click to enlarge and sharpen):

Too hard?  Fine, just remember this:

• Every increase in frequency is an increase in service hours, and thus in operating cost.  If you want to increase service on a line from every 30 minutes to every 15 minutes, that will double the cost of running the line.  This is why most transit agencies would like their service to be more frequent, but have trouble affording that frequency.  We explore frequency in Chapter 7.
• Every increase in average speed is a savings in service hours, and thus in operating cost.  If we can cut the cycle time of a line by 25%, that cuts its operating cost by 25%.  This is why transit agencies are always trying to control delay (Chapter 8).
• At low frequencies, operating cost is lumpy.  Because you can’t run a fraction of a driver, small differences in speed or frequency can create large differences in operating cost, if the overall frequency is low.

Frequency and speed are both great things for the customer.  But for the transit operating company, frequency costs money, while speed saves money.   When discussing the hard choices surrounding frequency and speed – choices that really pervade every part of this book – it’s essential to keep that in mind.  Frequency costs; speed saves.

First, here is a map of the Sydney rail network that may clarify the Lidcombe-Bankstown issue described in Chapter 4.  A train departing Sydney’s Central station with destination “Lidcombe” is probably travelling the orange line, which ends at Lidcombe, instead of one of the lines that’s useful for getting from Central to Lidcombe.  Lidcombe is a final destination, but  the orange line is U-shaped, so what matters at Central is that it goes via Bankstown, not that it ends at Lidcombe.  Lidcombe is the “TO” but in this situation, the “VIA” (via Bankstown) matters more.

On the other hand, if you’re considering the orange line from midpoint station such as Marrickville, the “Lidcombe” (TO) matters.  At this point, this  It’s telling you which branch the orange line will follow when it splits at Birrong.  But it’s also telling you, generally, that this train goes westward along the line rather than eastward. 

In signage, transit agencies need to think about whether, at a particular station or stop, the TO and VIA matters more — and if both are needed, which should be emphasized.  For fixed signage at stations, it’s not hard to adjust the content to say what matters from the perspective of that particular station.  If you can’t, do both: “Lidcombe via Bankstown” or even better (at Central) “Bankstown, and on to Lidcombe.”  The latter message properly emphasizes the direction of the train from the point of view of Central, while still signaling the onward path.  This method is almost never used, but there are many situations where it can be useful. 

For signage onboard transit vehicles, the content can now be made responsive to the vehicle’s location, so that signs are automatically updated when the vehicle passes a particular point on the line.  That suggests that bus signs could be more frequently updated to present just the information needed at the stops that it’s passing — which could make for much simpler and clearer signs.

Why care about signage?  Because clear signage makes the system look simpler, and suggests, more directly, that transit is ready to serve your freedom.  And because clarity and accuracy are beautiful.

For a more thorough discussion of the “to-via” problem in the context of Portland and San Francisco, dealing particularly with the pleasures and clarity that arise from naming lines after major streets, see this article. 

When the existing transit system doesn’t seem to be meeting the needs of your organization or interest group, it’s tempting to decide that you need a new route, or even a new network.  Service demands are often presented to transit agencies in the form of demands for a new route, and these are sometimes implemented even though they have a weakening effect on the whole transit network.  A good network is a set of services that are all designed to fit together and work together efficiently.  If you just add a route without rethinking the network, you’re almost always reducing the overall efficiency of the network — and thus its ability to get people where they’re going.

If you currently have little or no service, then of course you can demand new service.  But if you already have a transit network and just don’t find it useful for your needs, it’s important to ask whether an investment in that network would help fix the problem, rather than inventing a new service that will duplicate the existing one.

Requests for new duplicative routes often arise where transit service is already running, but:

• the frequency or span of service is inadequate, or
• the existing service is hard to figure out, or
• the existing service doesn’t stop exactly where you want, or
• the existing service is considered unacceptable in quality for a particular interest group’s needs, or
• a connection (transfer) is required for the trip that you care about.

Let’s look at each one.  At the end of this article, I’ll also come back to some practical considerations.

Frequency or Span of Service is Inadequate 

If you want more frequency or span (duration) of service, the last thing you want is a new service running on top of an existing one.  Frequency and span are expensive because (except on driverless metros) the cost of driver labor grows directly as you increase either of them.  Running twice as often doubles your operating budget, and so does doubling the number of hours per week that you run.

Operating cost also doubles with the number of route-miles or route-km you have to operate, so fewer routes mean more frequency.  So don’t propose a new route.  Lobby for more frequency and span on the existing one.

The Existing Service is Hard to Figure Out

Some published transit maps showing the entire network are so confusing as to be useless.  Frequent Network mapping is one solution.  But just because you can’t figure out the service doesn’t mean it isn’t there.  Demand that your transit agency create clearer information that makes the usefuless of the service to your community more obvious.  (I can help them with that!)  If your need is for downtown circulation, be sure to study the option of branding existing services as downtown shuttles.  

The Existing Service Doesn’t Stop Exactly Where You Want

If you represent a senior or disabled community for whom walking is a hardship, you probably do need your own route or service, or to be served by existing services — such as paratransit — specialised around those needs.

But if you’re an institution or organization that wants transit to stop closer to your building, a new route is unlikely to be the best solution.  A convention center or university, for example, can ignore the surrounding bus network and create a bunch of its own shuttles, but a whole transit system devoted to one destination isn’t going to be as frequent as what you could have if you worked with the system that exists.  Advocate for stops closer to your location.   

Note, too, however, that if your destination requires a deviation — typically because it’s set back from major streets — then transit can only deviate to you by infuriating everyone else that’s riding at that point.  In that case, depending on how big a market you are, the deviation may well not be justified.  In those situations, don’t invent a large shuttle system that you can’t afford to run frequently.  Instead, offer a really frequent shuttle by running the shortest line possible: a link from your destination to the nearest transit station where versatile service is availble extending in many directions.

Existing Service Quality is Unacceptable

All kinds of emotions get expressed through comments about service quality.  In some cities, for example, everyone is so attached to the idea that buses are only for the poor that the very idea of using the same buses for more diverse markets sounds absurd.  And in such cities, the quality of the bus service may have deteriorated to the point that broadening their market is simply impractical.

On the other hand, many transit agencies are developing the ability to meet customers part way on quality.  Transit service will never be luxurious, but the look-and-feel improvements in the bus over the last 20 years have been truly transformational.  So before you insist that your city’s buses are useless, ride one of the newer ones.  

There are things that you as a civic advocate can do about bus quality to bring it closer to what your constituents need.  You could demand the abolition of bus wraps that cover windows and make interiors gloomy.  You could advocate for a focus on customer experience in purchasing.  Understand that these things cost money, but they may be good long term investments if your view about the inadequate quality of your buses is widely held.  But you’ll get a better mobility out of these improvements to the commons than out of advocating a separate service just for your needs.

Existing Service Requires a Connection (transfer)

Efficient, abundant transit networks often require connections, because you can’t run direct service from everywhere to everywhere else.  This issue is discussed in Chapter 12 of Human Transit, but for a simple case study underlining the futility of new routes designed to avoid connections, see here.

Plan for Versatility

A very frequent transit line — and one that can justify other improvements such as good amenities and transit lanes — is designed for versatility.  It does not serve any particular identified interest group, but instead aims to be useful to many kinds of people for many kinds of purposes.  It does this by running straight, with a reasonable spacing of stops to ensure speed.  It also does this by forming part of an interconnected network.  Remember, it’s not the route that’s designed, but the network.  A route may be designed as it is partly because of how it fits into the larger structure that enables people to get wherever they’re going, not just to destinations along one route.

So if your mission is to serve a whole city or region, designing a transit route around any self-identified group of people is usually a bad idea.  Most successful and attractive transit seeks maximum versatility, by serving the most diverse possible range of demographics, trip purposes, and origin-destination pairs.  You can make exceptions where a single demographic group produces sufficiently massive ridership, as in some commute markets.  But in general, the way people self-organize and self-identify politically is a bad guide to how to meet their transit needs efficiently.  Everyone can draw the perfect transit line just for their interest group, but such proposals tell you nothing about what a good transit system would look like — one that maximized everyone’s ability to get where they’re going.

This series of articles is closed to comments, but you can comment here.

Placeholder for discussion of the to-via problem.

Placeholder for discussion of operating cost.

Placeholder for discussion of personal mobility.

Test page for Chapter 8 detail.

This isn't about transit, but it's about loving the city.  For the holiday weekend, some selections from the plywood that still covers storefronts broken in Vancouver's 2011 Stanley Cup Riot. These are from the Chapters bookstore at Robson & Howe.

"Previous generations found freedom and flexibility through the car.  But Generation Ys find their freedom and flexibility by staying connected to their friends, family and workplaces through the various information devices – like their laptops, or iphones.

"They can stay connected on a bus or a train. They can bring the office with them. They can bring their study with them. They can bring their friends with them. They can't if they're driving."

— Peter Newman, Curtin University, Perth, Australia, quoted in the West Australian

Joshua Arbury of Auckland Transport Blog ruminates further.

“Awesome!  Clear and challenging!”

“Well done!  Would like to see this course offering annually, widely advertised to municipal staffs.”

“Excellent instructor.  A lot of information with a high degree of clarity.”

On the East Coast? Come to our two-day course in NYC February 6&7, 2014!

 “Transit Network Design: an Interactive Course” is designed to give anyone a grasp of how network design works, so that they can form more confident and resilient opinions about transit proposals.  Any institution or organisation can sponsor the course.  So far, it has been offered through universities, professional organisations, and transit authorities. 

Much professional training in transit will teach you about quantifying demand, understanding statistics about what transit achieves, studying the features of the various transit technologies, and seeing how transit relates to other goals for governments, individuals, and businesses.  All that is valuable, but there’s a piece missing: Few people get hands-on experience working with transit as a tool, understanding how to use this tool to build a transit network. Learning to think creatively with these tools is the essence of transit planning.

I believe in teaching transit planning the way you’d teach carpentry.  A carpentry class might involve a lecture about the physical structure of wood and how to not kill yourself with a saw, but after that, you’ll only learn carpentry by doing it. 

The course is a built around a series of exercises where students work together to design transit networks for a fictional city, based on its geography and a set of cost limitations.  The exercises let students learn the basic tools and materials by actually working with them to develop creative solutions to a series of planning problems. 

Issues covered include network design, frequency, right-of-way, basic operations costing, and interactions with urban form.   This course is well suited for professionals, students, community leaders and local government staff. 

The course is done in intensive format covering one or two days. Longer versions can be developed on request. About 60% of class time is in interactive exercises, while most of the rest consists of group discussion based on the results of the interactive work. 

 What Students Have Said

“Jarrett Walker’s two day transit network design class explores the intricacy of designing transit networks, touching on elements ranging from maximizing the utility of a strained, underfunded bus system to planning high capacity bus and rail lines.  This is the kind of modern design that transit agencies should be using to attract new ridership.”  — Mike Cechvala

 “The actual design of the games was fascinating and would be a very useful exercise for any transit system to employ in a variety of situations. — Christopher MacKechnie, publictransport.about.com

“The game format … was great, and it really spurred us to focus on the planning process and understanding the tradeoffs that we were making, and not “force” specific outcomes.”

Recent Sessions

• Simon Fraser University.  Surrey, British Columbia.  Two-day session marketed to the public as part of City Program (continuing education).  June 2011.

• Licensed Professional Planners Association of Nova Scotia, in association with Halifax Regional Municipality and Dalhousie University.  Halifax, Nova Scotia.  One-day session marketed to mainly to municipal planning staffs.  June 2011.
• TransLink (public transit agency).  Vancouver, British Columbia.  Two-day session for internal staff, mostly not transit planners but in adjacent fields including operations and marketing.  June 2011.

• BC Transit (public transit agency).  Victoria, British Columbia.  Two-day session for internal staff, mostly not transit planners but in adjacent fields including operations and marketing.  September 2011.
• Sound Transit (public transit agency).  Seattle, Washington.  One-day session for internal staff, mostly not transit planners but in adjacent fields including operations and marketing.  December 2011. 

• University of Technology, Sydney.  Sydney, Australia.  Two-day version for a mix of graduate students and professionals in land use planning and local government.  March 2012 and again in October 2012.

• MAPA COG (regional planning agency).  Omaha, Nebraska.  One-day session of leading stakeholders of all kinds, in the context of the beginning of a regional transit planning effort.   September 2012.

If your organisation or institution is interested in offering the course, contact me using the email button under my photo! –>

[Photos: Heather Ternoway, Dalhousie University, Halifax]