Ensuring the Efficient Workings of a Bike-Sharing System

» Washington releases preliminary information about bike-sharing station locations. Are they positioned to succeed?

After the opening earlier this year of major bike-sharing systems in Denver and Minneapolis, Washington expects to relaunch its own program this fall. Working with Arlington County, Virginia, the U.S. capital will replace the only marginally successful 100-bike, 10-station SmartBike DC network installed in 2008 by Clear Channel with a 1,100-bike, 114-station system using Montréal’s Bixi technology, also under development in London, Boston, and Melbourne. Washington’s success, along with that of the several other American cities currently pushing these public cycling systems, will determine whether similar networks will spread to large and medium-sized cities across North America.

This recent focus on bike-sharing is a response to the strong public reception to systems in European cities like Paris and Barcelona, where thousands of people hop on the publicly owned vehicles everyday. In the French capital, where more than 20,000 bikes are available in the city and in the near suburbs, bicycle mode share has doubled since 2007.

Washington’s Capital Bikeshare will initially feature one hundred stations in the District of Columbia and fourteen in Arlington’s Crystal City, but future expansion — potentially funded by the federal government, depending on the outcome of the region’s application to the TIGER program — could result in an eventual quadrupling of the system’s size. Future bike stations could be positioned in Maryland’s Montgomery and Prince George’s Counties, in addition to Arlington’s Rosslyn-Ballston Corridor and the City of Alexandria.

This week, though, Washington revealed preliminary station locations for the first stage of the system, a few weeks after Arlington pinpointed its own. Have the cities’ transportation planners thought through how people are likely to use these bikes? Or is the District limiting the chances for the system’s success by not fully considering the needs of potential bike riders?

To consider these questions, it’s worth comparing the proposed system with the existing and well-used systems in Montréal and Paris. One place to start is an evaluation of station densities. In a bike share system, a station is where people pick up and deposit bikes; it typically includes ten to twenty “docks,” each holding one bicycle. The system works by allowing customers to choose a bike at one station and deposit it somewhere else. The density is a reflection of how far a person has to walk to get to or between stations.

In the chart below, I’ve taken one mile-square samples of central city neighborhoods and peripheral neighborhoods and plotted station locations on them; the former are the densest station areas in each respective bike system (downtown D.C., downtown Montréal, central Paris) and the latter are those that are least well served by stations (Anacostia in D.C., southeast of Parc Maisonneuve in Montréal, and Montreuil east of Paris). I obviously haven’t included areas outside the reach of the bike share networks.

The charts demonstrate the fundamental difference between Washington’s proposed system and those in Montréal and Paris. In the center-cities, the French-speaking cities have roughly three times the densities of bike stations as the District proposes; in areas far from downtown, the difference is even more pronounced. Indeed, the minimum density of stations anywhere in the Paris or Montréal bike-sharing zones is higher than the maximum density promoted for Washington.

This could potentially cause significant problems for the users of the new U.S. capital system.

There are two main reasons for this: One, light station density makes short neighborhood commutes via public bicycle more difficult, reducing the chance to attract occasional riders; Two, insufficient density can cause logistical problems in situations where stations either run out of bicycles or, inversely, run out of dock spaces — not infrequent issues, at least considering my own experience using the Parisian system extensively.

Washington has clearly attempted to spread out its initial investment, giving at least a few stations to every part of the city. This, however, would result in a limited concentration of bikes in the relatively large areas east of the Anacostia River (just 11 stations) and west of Rock Creek Park (9 stations). Each of these sections has a lower population density than the rest of the city.

This contrasts significantly with the approach in Paris and Montréal, where the bike-sharing zone ends abruptly; there isn’t much of a station density fall-off below the 15 stations per square mile mark. Even in areas with low densities, such as in the examples shown on the chart above, stations are clustered along corridors, ensuring that virtually every station is within 200 meters (656 feet) of the next. This allows people to walk easily between stations if they encounter some problem.

Closeness of stations is essential to making bike-sharing work. Washington has designed its system as if people can pre-plan specific commutes from one station to another, but that’s not always a realistic option. For one, unless stations are very well marked from the surrounding streets, it is not always easy for bike riders to find even a predetermined destination station unless they’re very familiar with the neighborhood. This could complicate matters, since in modern bike-sharing, customers face increasing financial penalties the longer they delay returning their vehicles. The more stations, the easier it is to find one; it’s okay to end up parking somewhere different than originally planned as long as the station is relatively close to where you want to go.

Meanwhile, the lack of adjacency between stations could become extremely difficult when stations are either empty or full. For commuters hoping to ride a bike in a neighborhood with few stations, an empty station means they must either choose a different way of getting around or walk a long distance to the next station. On the other hand, a full station at the end of a trip could mean having to park at an area that is completely out of the way.

Though there are municipal employees using trucks to move bikes from full stations to empty ones, they frequently cannot keep up with the movement of traffic during the day, leaving people in the lurch when there aren’t nearby stations to choose from. These are technical problems that will limit the appeal of using bike share for a large percentage of people in the under-served areas — which is specifically why Montréal and Paris have chosen not to have any neighborhoods with just a few stations.

The foreign example suggests that you either have to put a lot of stations in a community, or not serve it at all. It’s the low station density middle ground that causes problems.

All that said, there are several reasons to remain optimistic about the implementation of bike-sharing in Washington. For one, even if station density isn’t as high as it ought to be, people are still likely to use the bikes at a rate that expands their overall mode share in the city. Second, there is a significant chance that the municipality will be able to find sufficient funds to expand the project to increase station density in areas that are initially under-served; in terms of transportation capital investments, bike share is pretty much as cheap as you can get. But there’s always the problematic possibility that expansion could mean only extending the system further out with low station densities, not increasing densities within the already served areas.

Yet Washington will have an example of what denser station areas look like right on its home turf. Arlington County’s fourteen stations are all within the tight confines of the adjacent Crystal City and Pentagon City districts; each station is within just two or three blocks of the next. This will provide a working example for how the bikes can serve as efficient neighborhood transportation devices, getting people between relatively close destinations more quickly than is possible with walking.

Related: If you understand French, here’s a funny satire video that proposes a new way of thinking about bike share as a political tool in the Paris mayoral race. Image at top: Montréal Bixi bike share stands, from Flickr user newton64 (cc)