Temporal Discounting in Travel Distance Perception: Implications for Transit Design

Abstract: Travel time heavily influences transportation choices, with public transit often perceived—and often proving—to take longer than personal vehicles. Yet, how people psychologically process travel time across modes is underexplored. Common beliefs suggest public transit feels slower, but the specific metrics behind this perception are unclear. For instance, how much does perceived time deviate from actual time, and does this gap widen over longer trips? Understanding how perceived and actual travel times differ, and whether this difference scales with distance, could help design public transit systems that address psychological biases, encouraging broader use.

This study examines how travel time estimates vary across distances and transportation modes, and whether individual biases, such as temporal discounting, influence these estimates. We also explore whether this aligns with a known temporal perception pattern where shorter durations are overestimated and longer ones underestimated (Vierordt 1868), reflecting a tendency to regress toward the mean (Stevens and Greenbaum 1966; Hollingworth 1910). Specifically, we investigate whether a shorter-distance trips lead to greater overestimation than longer ones.

In this study, 80 participants were shown fictional commuting scenarios featuring one of four transportation modes (bus, advanced bus, carpool, or self-driving) and maps indicating a route of either 2, 5, or 10 miles. Participants estimated travel times for each scenario. To standardize travel-time estimates across distances, we calculated the ratio of estimated travel time to route distance and subjected these ratios to a 3 Distance x 4 Transportation Mode within-subjects ANOVA. We also included temporal discounting tendency, measured with the Hardisty and Weber (2009) discounting battery, as a covariate.

Results indicated that both distance and mode of transportation significantly influenced perceived travel time, with a significant interaction between the two. Consistent with previous findings, participants overestimated travel time for shorter distances relative to longer ones. Notably, while estimation errors were more similar across transportation modes at shorter distances, they diverged significantly at longer distances, with public transportation modes being greatly overestimated. When controlling for temporal discounting tendencies, the main effects remained, but the interaction between distance and mode weakened. This suggests that while both distance and transportation mode affect perceived travel time, the tendency to overestimate travel time for public transport on longer trips is influenced by individual differences in temporal discounting. These findings have important policy implications for transportation agencies.

By understanding the psychological factors influencing travel time perception, transit agencies could improve shorter routes where overestimation is common, making public transit more appealing. Targeted transportation demand management strategies like real-time updates, better trip-planning tools, and marketing that highlights actual travel times could help reduce the perception that public transit is slower for longer trips. Ultimately, these strategies could increase ridership and optimize public transit to better align with commuters’ perceptions of travel time.