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What’s mass transit worth to you? It depends on how close you are to it. “Proximity matters,” says Matthew Kahn, a Tufts University economist and co-author, with Brown University economist Nathaniel Baum-Snow, of a new study of urban rail transit expansion and its impact in 16 cities, including Boston, from 1970 to 2000.
“When commuters live and work near the central business district, they tend to use public transit,” says Kahn, who came to speak at Harvard’s Kennedy School of Government in a forum sponsored by the Rappaport Institute for Greater Boston December 7. But as people live and work farther out, transit usage plummets, he says. Commuters living four to seven miles outside city centers showed the largest decline in usage over the 30-year period. People living more than 18 miles out didn’t use public transportation in 1970 and they don’t use it now, he reports.
So who gets the most out of rapid transit? “Rail transit expansion is really good when you go from one dense area to another dense area, especially [if] at one end at least you can walk,” says Richard Voith, a transportation and urban economics expert at Econsult, a Philadelphia–based economic consulting firm, who teaches economic development at the University of Pennsylvania’s Wharton School.
In Greater Boston, mass transit riders declined from 18 percent of all commuters in 1970 to 14 percent in 1990, then inched back up to 15 percent in 2000. Over the long term, Boston’s public transportation usage is contracting, though more slowly than in other major metro areas, Kahn says.
Baum-Snow and Khan also conducted research into the differences between subways that primarily serve commuters who walk to stations and those who drive to them. The usage of both types of stations increases with additional service, but park-and-ride stations show a greater ridership increase than walk-and-ride stations do. Comparing census tracts within one kilometer of the walk-and-ride Davis and Porter stations on Red Line stations in 1990 to those same census tracts in 1980 (before the Red Line expansion in 1985), this research found a 5.5 percentage point increase in public transit usage after expansion. At the park-and-ride Alewife Station, there was a 7.8 percentage point increase in ridership.
Transit expansion produces certain benefits, however, that are greater for communities near walk-and-ride stations. The number of college graduates increased by 14.2 percentage points near Red Line walk-and-ride stations. Walk-and-ride stations were associated with much more gentrification, says Kahn, while there was “no yuppie effect” at park-and-ride stops. Home prices increased by 23 percent in areas that gained a Red Line walk-and-ride station. But housing prices near Alewife Station actually declined slightly —consistent, Kahn says, with complaints about noise and congestion from residents near park-and-ride stations.
But these are just the first steps in thinking through the costs and benefits of rail transit expansion, according to Kahn. “We need to know, how does ridership change and how does the composition of communities change,” he says.
If the goal of new stations is to increase ridership, park-and-rides are achieving that, says Kahn, but other goals, such as making the neighborhoods around them desirable, remain elusive. He suggests that communities accepting park-and-ride stations might be compensated for quality-of-life disruptions, such as traffic congestion.
