Randomized Controlled Trial (RCT) of...
Free or Discounted Public Transit Fares for Low-Income Households
Reviewed
SSRN (June 2025) published RCT results for a program offering free or 50% discounted public transit fares to low-income households in Allegheny County, Pennsylvania (including Pittsburgh). Despite the abstract’s positive portrayal of the findings, the study found negligible impacts on the two prespecified primary outcomes – workforce earnings and primary healthcare utilization – during the 18-month program.
Can reducing public transit fares improve mobility and socioeconomic outcomes for low-income individuals? We conduct a randomized experiment that offers fare discounts to 9,544 low-income households in one large U.S. county. Households are randomly assigned to receive no discount, a 50% discount, or a 100% discount on all public transit trips for 16 to 19 months. We measure participants’ mode-specific travel behavior using a combination of smartphone GPS data, high-frequency surveys, and farecard transactions. GPS data indicates that free fares increase transit ridership by 43% relative to status quo prices, accompanied by a shift away from private vehicle use along several margins. Half-price fares yield no change in transit ridership. Both discount levels improve self-reported mobility capacity, but neither one increases the overall frequency or spatial breadth of travel. Among those unemployed at baseline, free fares cause a 3.5 pp increase in the likelihood of being employed and a $2,845 increase in total earnings during the first six quarters. The social welfare impact of free fares exceeds the fiscal cost of the policy during the first two years. Fare-free transit shows promise as a means of helping disadvantaged job seekers and as a tool for mitigating the environmental externalities of car travel.
Can reducing public transit fares improve mobility and socioeconomic outcomes for low-income individuals? We conduct a randomized experiment that offers fare discounts to 9,544 low-income households in one large U.S. county. Households are randomly assigned to receive no discount, a 50% discount, or a 100% discount on all public transit trips for 16 to 19 months. We measure participants’ mode-specific travel behavior using a combination of smartphone GPS data, high-frequency surveys, and farecard transactions. GPS data indicates that free fares increase transit ridership by 43% relative to status quo prices, accompanied by a shift away from private vehicle use along several margins. Half-price fares yield no change in transit ridership. Both discount levels improve self-reported mobility capacity, but neither one increases the overall frequency or spatial breadth of travel.
Both free and half-price fares had negligible impacts on the study’s primary outcomes – workforce earnings and primary healthcare utilization – during the first six quarters after random assignment. An exploratory analysis of the subgroup of individuals who at baseline had recently become unemployed found that
Among those unemployed at baseline, free fares caused a 3.5 pp increase in the likelihood of being employed and a $2,845 increase in total earnings during the first six quarters
- a finding that may warrant examination in future research. Exploratory analyses also suggest
that the social welfare impact of free fares exceeds the fiscal cost of the policy during the first two years. Fare-free transit shows promise as a means of helping disadvantaged job seekers and as a tool for mitigating the environmental externalities of car travel.
No-Spin’s Study Overview
Large, high-quality RCT of a program offering free or discounted public transit fares to low-income households in Allegheny County, PA (including Pittsburgh) finds negligible impacts on the two prespecified primary outcomes – workforce earnings and primary healthcare utilization – during the 18-month program.
Program and Study Design:
- 9,544 adult, working-age recipients of Supplemental Nutrition Assistance (SNAP) were randomly assigned to receive either a 0%, 50%, or 100% discount on all Pittsburgh Regional Transit bus and light rail trips for approximately 18 months. Recipients could include their children in the fare discounts.
- 72% of sample members were female, 59% were Black, 57% were not employed at baseline, and 64% had no more than a high school education.
- Based on our careful review, this was a high-quality RCT (e.g., baseline balance, negligible attrition on the primary outcomes, prespecified analyses).
Findings:
- Free fares (100% discount) increased transit ridership by a statistically significant 43% – i.e., 1.48 trips per week – during the 18-month program, compared to the control group (0% discount). Half-price fares (50% discount) did not discernibly increase ridership.
- Despite increasing ridership, free fares did not discernibly increase earnings during the 18-month program (the free fares group earned an average of $17,483 over the 18 months versus $17,289 for the control group – a difference that was not statistically significant). Similarly, half-price fares had no discernible impact on earnings versus the control group.
- Free fares did produce a small, statistically significant increase of $183 (about 6%) in earnings in the third quarter after randomization, compared to the control group, but had no significant impact in any other quarter or cumulatively over six quarters (18 months).
- Neither free nor half-price fares produced a discernible impact on the number of days with non-ER outpatient health care (an approximate measure of primary healthcare visits) over the 18 months, compared the control group.
Comment:
- Allegheny County reports that it used the results of this study “to inform the design and implementation of a longer-term program called AlleghenyGo, which offers a 50% PRT discount for working-age county SNAP beneficiaries and their children.” The County’s summary of the study’s “key takeaways” – like the study abstract – omits the null primary findings and highlights the post-hoc subgroup results.
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