Experimental evidence on the effects of means-tested public transportation subsidies on travel behavior

Means-tested reduced transit fare programs are increasingly prevalent. This paper describes the results of a unique experiment in which a randomly selected group of low-income individuals in King County, Washington received up to six months of free public transportation. We leverage the experiment to explore how public transit's cost affects mobility. Using administrative data tracking transit card taps on King County's fleet of vehicles, we find that free fares sharply increase transit card use. Follow-up surveys corroborate an increase in travel by public transportation, but also indicate that some of the treatment effect on transit card use is driven by payment method substitution. Treatment effects on overall travel by any mode are less clear. Finally, we find little persistent impact of free fares on transit card use after the subsidy ends.