In Cities, Transit Isn’t Just for Commuting

Alon Levy of the Pedestrian Observations blog compares commuter ridership on urban transit and commuter rail. He finds that in San Francisco the total number of riders on four parallel east-west Muni bus routes serving the central business district is almost twice the maximum number of commuters:

This represents an implausible 184% mode share, in a part of the city where a good number of people own and drive cars, and where some in the innermost areas could walk to work. What’s happening is that when the transit system is usable, people take it for more than just their commute trips.

He then looks at the Massachusetts Bay Transportation Authority’s regional rail and riders coming into Boston’s CBD from suburbs and city neighborhoods near rail. Levy finds the mode share to be just 32 percent, and he notes that most commuters use other modes and very few commuter rail passengers are using rail for other non-work trips.

The difference between San Francisco and Boston is partly due to the geographic distribution of the non-work places people need to reach for shopping, errands, and services. In a city, travelers can use transit to reach these locales, but they are more likely in the suburbs to drive to them.

Levy also says that regions with transit systems that cater to commuters — trains arriving once an hour during off-peak hours, for example — will not be able to attract other types of riders. "If the station placement is designed around car travel, as is the case for all American commuter lines and some suburban rapid transit (including the tails of BART), then people will just drive all the way unless there’s peak congestion. Only very good urban transit can get this non-work ridership," he says.