Motivating commuters in highly urbanized areas to use mass transportation can reduce commuting costs generally. If workers commute in ways that reduce traffic congestion, all commuters in an area may enjoy spillover benefits such as lower transportation costs, shorter waiting times in traffic, and improved air quality.
The work of Andrea Hamre at Virginia Tech has reached similar conclusions. In research from 2014, focusing on Washington, D.C., she and Ralph Buehler found that parking and transit benefits together led to an increased probability of driving to work, relative to a world with no benefits. Hamre recently expanded that study to five cities (Baltimore, Philadelphia, Newark, and New York, as well as D.C.)—and discovered that the same patterns held true.