Public transport vouchers to enhance ridership: Mental accounting bias in frequent public transport users

The widespread adoption of smart travel cards has substantially enhanced the flexibility of pricing mechanisms in public transport. This study examines the impact of a monthly voucher on increasing the utilization of public transport services. The analysis is based on a controlled field experiment conducted within Bogotá’s public transport system. We provide empirical evidence of the presence of Mental Accounting Bias (MAB) in the context of transport voucher use. Specifically, we demonstrate that the increased ridership observed among voucher recipients can be attributed not only to the voucher’s monetary value but also to a behavioral response triggered by a perceived expansion of their transport budget. This finding highlights the role of MAB in explaining why this intervention was effective, whereas other demand-side subsidies, such as fare discounts, have proven less successful in this context. To establish the presence of MAB, we employ three distinct methodological approaches, each drawing on different sets of evidence collected during the experiment. They provide compelling evidence of MAB. To our knowledge, this study presents the first empirical investigation of MAB in public transport. The potential to induce MAB through transport vouchers offers valuable insights for the design of policies aimed at increasing public transport ridership.