Complementary Modes Should Be a Primary Local Planning Goal

In earlier posts I highlighted the breadth of complementary transit systems that exist along with primary ones in New York City, and in another I proposed that transport project evaluation should account for pricing and zoning policies in place before new investment is made. Here what I argue is that the complementary aspects to any primary transport system are nearly always local concerns, and too little is known about how complementary local policies can make or break successful primary systems.*

One way to think about urban transport networks is that there are primary systems complemented by secondary systems. The primary systems are the highest capacity networks, spatially fixed and designed to broadly serve the population of the region. Freeway networks, rail transit and bus rapid transit are examples of primary systems in this way. Secondary systems are those that serve smaller, sometime niche, populations and act as complements to the primary systems. These secondary systems are critical to the overall success of the transport networks as primary systems are very good at serving predictable travel such as rush hours but less adept at serving lots of different types of trips to lots of different places.

One reason automobility is so pervasive is that the primary systems (freeways and other large roads) are nicely complemented with hosts of local policies that make driving really easy. Parking requirements, street design, signal timing and other aspects all come together to create a seamless driving experience in most US cities. No other travel mode has such an advantage and transit, taxis, cycling and walking are too often left to cobble together whatever kind of system they can. Rarely are these “alternative” modes granted the luxury of integrated primary and secondary systems, and even more rare are integrated transportation providers that manage all primary and secondary transportation. Transport for London is an example of an integrated approach.

Consider the U.S. investment made in transit over the past few decades. Transit now accounts for close to 20 percent of total Highway Trust Fund spending, yet the share of travelers using transit has barely moved nationally. This is not an indictment of transit as a worthy mode, just suggestive that we can spend that money more wisely. New York City is a true success story for transit ridership yet has received very little new investment for system expansion relative to maintenance costs (mostly through state of good repair programs) and broadly supportive complementary systems of taxis, liveries, jitneys and 24-hour service. Parking is also very expensive in New York and often not required for new construction and adaptive reuse. Road tolls—which account for about 25 percent of all road tolls collected in the country—have increased dramatically over the past few years. Over the past decade transit fares have been followed by increased rail ridership, though fares have largely kept pace with inflation since 2003. This does mean that New York’s relatively high farebox recovery rates —for the U.S.— have remained an important source of operating revenues. Taken together New York is doing lots of different things that support robust transit services that have little to do with the built environment and density, though these obviously help, but lots to do with complements to the primary systems.

Other cities certainly do a lot to support transit investment, but none support alternatives to the auto to the same degree that autos benefit from complementary policies. One challenge for cities is that the available complementary systems are not very well understood. As one example, current policy debates about taxi services and app-based ridesharing companies often minimize the complementary role of taxi services for transit-oriented cities. Even car sharing studies have largely viewed car sharing as a replacement for auto ownership (e.g. “how many cars does a shared car replace”) rather than an extension of transit policy (“how can shared cars extend access for transit users?”**). Obviously there are nuanced analyses of these complementary systems and the researchers involved know this. The point is that many systems that are sometimes considered substitutes (car sharing or taxi services) are more accurately considered complements, and necessary but not sufficient systems to support primary transit and road networks.

Another challenge for complementary systems is that autos are sufficiently utilitarian that once a city is designed for cars then all trips can be made with one vehicle. Auto drivers are unimodal, whereas transit riders, walkers and cyclists tend to use many more modes through the courses of their lives. This means that complementary systems for non-auto uses require many different types of investment, many of which will have small obvious payoffs. Less obvious payoffs may be large, however, which is a large reason we should study complementary modes more. For instance, based on work by Dan Hara in San Francisco we know that people are much more likely to take transit to work if they know they can get home by taxi if they have to work late. This holds even though most never use the taxi option. In New York it is common for office workers to get a guaranteed taxi ride home if they work past a certain hour (9pm in many cases). This program leverages the availability of complementary travel modes to reinforce the primary transit modes.

By focusing on complementary secondary transport systems cities can lay the groundwork that supports investment in primary systems. Investment in primary systems alone will not produce modal shifts. What if Interstate freeways had been built without minimum parking requirements as part of the zoning code, or a hierarchy of road networks designed to funnel drivers onto ever-faster roads? US cities would look and function very differently. The policy shifts toward automobility was comprehensive and included federal, state and local policies all working together to complement each other. Such voluntary coordination simply does not exist for any other mode.

*A search for “complementary transportation” returns pages of results that misspell “complimentary”.

**Many car share studies and advocacy pieces do mention access to cars for those who don’t have one as a benefit, but most research examines how car share can reduce the need to drive by car owners.