The Challenging Questions of Public Transit

I love when small events create profound change–or the potential for it. In a short instance, previous notions are erased and rewritten with a whole new narrative. I recently experienced one of these moments while reading Jarrett Walker‘s book Human Transit: How Clearer Thinking about Public Transit Can Enrich Our Communities and Our Lives. For the first time in my professional life, I sensed a great amount of compatibility with an occupation. My engineering background, design skills, and profound passion for developing community overlap so beautifully with transit planning that I couldn’t help but gobble up each page with fervor and inspiration. Backed by decades of transportation consulting, Walker gives life to the basic principles of designing and evaluating public transportation systems. Written for the layman, Human Transit provides the reader with four fundamental considerations in which every transportation agency should ask themselves. For my own learning and with the hope of spreading his teachings, I detail Walker’s conclusions in my own words. Furthermore, I relate these four major concepts to events you may experience while using public transit.

The Plumber Questions

Walker refers to these four fundamental trade-offs as the “plumber questions” because of their complex nature. As with most multi-dimensional problems there is a short-term and long-term solution, with a spectrum of choices in between. For example, fixing a leaky pipe comes at various time, material, annoyance, and financial-dependent fixes. You could replace the entire system or just one piece. You can simply duct tape the leak and worry about things in the spring. Or perhaps you decide it’s cost-effective to learn the plumbing trade rather than contracting the work. What’s more, you could decide to sell the house entirely, bestowing the leak onto the next owner.

These trade-offs are common with large, complex issues where one variable impacts others in a variety of ways.

In this sense, fixing a leak and designing large-scale public transit isn’t all that different. There are a variety of ways to reach an end goal, and the answer to each question exists on a spectrum. For example, an agency providing door-to-door service or bus transfers are both viable options–one may be preferred over the other, but neither is necessarily wrong. Whether a plumber or city planner, you have to take into account stakeholder’s needs, budget, objectives, and interests in designing a robust solution. Walker argues that designing a sustainable, functional, and effective transportation system will take the following four “plumber questions” into account:

  1. Ridership or Coverage?
  2. Connections or Complexity?
  3. Peak-first or Base-first?
  4. Exclusive or Compromised Right-of-way?

Despite their appearance, these are not binary choices–they are a complex spectrum of solutions. Choosing one aspect will invariably affect on another. Whether or not you use public transit, its existence impacts your community and how you move through it. I hope shedding some light on these questions will give you a better sense of transit design consideration and help you develop an appreciation for the nature of these decisions.

For the sake of this discussion, I will frame the transportation vehicle as a bus–although it could easily be modified for a rail car or ferry. Let’s dive into each of these design questions and connect the dots with personal experiences.

1. Ridership or Coverage?

I’ll begin this first question by defining a couple terms. Ridership is a metric measuring how effective a bus system is given a fixed budget. In other words, if allocated a set amount of money, how can we design transit to make as much money as possible? If we run buses on very busy streets during high-traffic hours, we’re bound to fill our buses to the brim. From a ridership perspective, we have maximized effectiveness–mile for mile, we’re boarding many passengers and receiving a lot of fares.

Coverage can be thought of as how prevalent the service is to all peoples from a geographic, socioeconomic, or accessibility standpoint. Prioritizing the coverage approach will provide an equitable bus system in which all tax-paying citizens of our city participate. In other words, we’re not trying to simply target the most profitable routes, but also places which service us less riders. To some extent, this allow everyone to enjoy the benefit of public transit. Here we arrive at our first conundrum: do we want to run our buses on the busiest and most profitable routes (earning us lots of money), or do we want to run on all streets, effectively increasing access to all people (everyone will feel serviced)?

If you are lucky enough to afford living in a desirable, up-and-coming neighborhood, you love your service frequency and reliability. But what if you need to live in a more affordable district further away from a commercial zone?  You may have to walk 1/4 mile to access the bus system. In this case, you are experiencing less coverage. This may discourage you altogether from participating in the city’s transit system. When determining where to live, it’s best to take this into consideration and move to affordable, but well-serviced areas. With a fixed budget, transit agencies decide which areas to cover while still making a profit.

2. Connections or Complexity?

Have you ever opted against taking transit knowing you would have to make a connection? There is undoubtedly a sense of inefficiency perceived by getting on and getting off. Having to wait (a second time) sounds like a big pain…and who knows if that second bus will actually arrive in a timely manner? Have you wondered why there isn’t a bus running directly where you need to go? In those moments, you are experiencing the fallout of our second plumber question.

On second thought, I’ll just drive. Transit doesn’t have to be confusing!

Let’s say our transit system attempted to eliminate transfers altogether. This way, everyone can get to where they’re going without the headache of connecting. So we start out by asking citizens to list their most frequent trips. They reply: work, home, the local farmer’s market, bank, their favorite taco truck, the park in which their kid plays soccer, and a salon.

If a transit system eliminated transfers completely, pretty soon bus routes would be titled “Route 47: Chris’s Apartment to Bank of Seattle“. After a while, our transit system would become so complex, we’d basically be running a door-to-door service. Thousands of routes later, our transit team goes bankrupt. This is a very inefficient way to design public transit.

Much to my surprise, transfer are a very critical and important function of public transit.

Transfers allow many people to go many places in a single system and subsequently, less routes than our pseudo-taxi service. In order to make connections more attractive, we have to run each route more frequently. This will give people faith that making a transfer will be a brief and (hopefully) enjoyable experience. Again, there is a trade-off between making you transfer every time you interact with transit or providing direct service between two locations of your choosing. The former provides widespread accessibility and frequent service while the latter begets complex transit maps and less frequent bus stop arrivals.

3. Peak-first or Base-first?

The third plumber question is a little more theoretical than the physical concept of transferring. Whether you bus, rail, drive, or walk, your daily commute often takes place at the same time. Compound that with every other citizen in town and you start to have peaks–or frequent travel periods. We generally refer to these periods as traffic or rush-hour.

Thanks to reloadable RFID transit cards and laser counting technologies, it’s easier than ever for transit agencies to measure how often (and at what time) people get on and off transit. Armed with this data, planners can map ridership vs time to observe peaking. The following graphs are identical curves showing number of bus riders versus time. In my fictitious city, there are two distinct peaks: one between the morning and afternoon and another between the afternoon and evening. The specific time and duration of these events are moot points, but the manner in which we service the peak differs greatly.

Due to finite money, vehicles, and drivers, agencies can only run so many routes. Because of this, transit planners must decide how to allocate these resources: should they cater to the rush hour periods? Or should they ensure consistent all-day service? Of course, for many agencies, the answer is somewhere in between. In the following graphs, the red area indicates an agency’s primary service target while white space represents secondary periods of concern.

In a peak-first approach, transit agencies prioritize the two rush hours with more frequent service to handle the masses. Here, we neglect low ridership periods–early morning, mid-day, and late night–because fewer citizens ride the buses at those times. Hence, if you work a standard 9-5 job, you can rely on transit. If you are trying to commute at low ridership times (white), transit may disappoint you.

Peak-first ensures there is enough service at high-time (red), such as morning and evening rush hours, to meet demand. Service during the off-times (white) will lack bus availability–so plan your schedule around it.
Base-first ensures there is constant coverage throughout the day (red). You’ll be just as likely to access the bus at 5pm as you would at 2am. The rush hours periods when ridership is high (white) are not left underserved. This leads to crowded buses and increased freustrations.

In the second graph, the transit agency has prioritized a base-first approach. This demonstrates an interest in providing consistent bus service throughout the day regardless of high ridership times. However, we see peak periods (white) are now underserved. In a base-first approach, the periods of high ridership will turn down customers due to lack of available seating, buses, or enough vehicles on the road.

Cities with extremely concentrated business districts and many professional workers tend to see very distinct peaks during rush hour mornings and evenings. Hence, it is advantageous for planners to prioritize service to these folks. This doesn’t mean low ridership is neglected altogether, but service will be less frequent. On the other hand, large urban areas such as New York, London, or Tokyo will have peaking, but in less stark manners. With so many people on so many schedules, it makes sense for them to prioritize their base first–making sure everyone has a viable transit option regardless of their schedule. Again, they still run dedicated rush hours routes, but not to the same extent as cities employing a peak-first approach.

As you begin taking public transit, learn about express bus options, how late service run, and how to optimize your commute. Perhaps you can negotiate an earlier start and end time effectively halving your commute? See if you can identify whether your local transit agency prioritizes peak-first service or base-first service. Most likely, it’s a mix of both!

4. Exclusive or Compromised Right-of-way?

One of the most dreaded plights of any transportation mode are delays–regardless of my enthusiasm for transit, I despise them as well. Our fourth and final plumber question involves the manner in which our transit vehicles move through the city and why delays occur. The graphic below is a modified chart from Human Transit showing various “classes” or right-of-way scenarios in which a bus moves through the city.

Various bus classes describe how transit vehicles interact with their surroundings. (Credit: Jarrett Walker, Human Transit, Original: Alfred Twu)

Class A is involves an exclusive and separate lane in which only buses run and no traffic can cross. This grants transit the clearest and therefore quickest path between stops, effectively reducing delays to the picking-up and dropping-off of passengers. It also is the most expensive to construct as cities must develop dedicated structures. Class A designs are commonly used for light rail networks.

Class B right-of-way depicts a “bus only” lane designed exclusively for transit, but not separate from outside interference. Hence, a bus must still play by the rules of the road. It has to stop for traffic, allow pedestrians to cross, and therefore experience those dreaded delays. This is far less expensive than developing a raised Class A structure, but still requires proper signage and road markings.

Class C scenarios offer no exclusivity or separation from general traffic. Buses are on an equal playing field as cars and trucks. Therefore, they tend to experience even more delays than Class B transportation. Unfortunately, this comes at a price. If you have hopped off a bus during rush hour to simply walk to your final destination, you have experienced a disadvantage of Class C design. This doesn’t mean these right-of-way designs are not used. If fact, a majority of buses run in this manner. On a positive note, this configuration is simple and low-cost to develop.

Asking planners to design our city with this fourth and final question in mind directly impacts our perceived effectiveness of transit. When done properly, exclusive and separated lanes are fast and reliable. Unfortunately, constructing all routes like this would be drastically expensive. Not to mention we’d be living in a concrete jungle. Cheaper and more easily integrated with current infrastructure, Class C routes offer many advantages such as low cost construction and little maintenance. However, we must be willing to accept the many delays that come with it.

An Altered View of Public Transportation

Regardless of your previous notions, I hope you’ve been enlightened by the challenging and dynamic nature of public transit design. Like many complex systems, agencies are not flipping switches, but turning dials. These questions cannot be answered in a binary fashion, but along a spectrum. As cities grow and develop, planners must constantly ask themselves if they have these answers turned to the right setting.

What is the most optimum approach to ridership, coverage, complexity, peak service, or exclusivity now and into the future? Unfortunately, these answers are very much dependent on one another, and no matter the choice, someone will always be left disgruntled, underserved, confused, or disappointed. Furthermore, there are many outside influences which I didn’t touch on in this post: politicians, citizen activists, environmentalists, non-profits, and utilities companies just to name a few.

Next time you take public transportation, refer back to these four questions for a greater understanding and appreciation of the system. If your daily commute is not a viable options, riding transit at other times may provide you access to a new neighborhood, restaurant, and experiences. Learn to embrace transfers and their ability to get you to a large swath of destinations–it’s less inconvenient than you think! Develop a greater appreciation for people of all backgrounds on your local bus line–this is a service of the people, for the people, and by the people. The essential life values connection and community with our neighborhood and cities–using public transit is one way to experience this connectedness. Lastly, limit the use of your car (if you have one) and bike more often; it’s good for the planet.

A Personal Note

As I continue exploring the concept of essentialism, I tend to value my time more and more. One incredible benefit from doing so is creating space for wonderful opportunities and insights. If I was still in the throngs of full-time employment, I’m not sure Human Transit would’ve impacted me in the same way. As I alluded to earlier, I’ve never experienced so much excitement for a professional career path and I hope to continue exploring the field of transit. I wholly attribute this to the lack of distractions and time constraints I’ve experienced during the past few months. I wonder what else I’ve “passed up” in life. I’m not advocating we all quit our jobs, but I do ask you reflect on how you spend your time.


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