Measuring the Effect of General-Purpose Lane Reduction “Road Diet” Measures on Drivers’ Travel Behavior

This study is an investigation of the effect of general-purpose lane reduction policies—commonly referred to as “road diets”—on drivers’ travel behavior, focusing on changes in travel route, departure time, and mode choice. A stated preference–off–revealed preference survey targeting drivers residing in Seoul was conducted in November 2024, yielding 3,466 responses, of which 650 were identified as valid. The data were analyzed using an error component mixed logit model to relax the assumption of independence from irrelevant alternatives and to account for correlation across alternatives and repeated choices at the individual level. In the model, four options were considered: maintaining private car use without changes (status quo), changing travel route, changing departure time, and switching to public transportation. The results indicate that lane reductions significantly influence drivers’ decisions, with a stronger preference for altering travel routes and departure times than for maintaining original travel behavior. However, shifts to public transportation were less pronounced, as drivers more frequently chose to adjust their routes or departure times instead. These findings highlight the importance of accounting for behavioral responses when implementing lane reduction policies and suggest that complementary measures, such as improved public transportation services and targeted incentives, may be necessary to encourage more substantial and sustained shifts toward public transport use. Future research should be conducted to examine the long-term effects of lane reduction and the interaction between such policies and public transportation improvements.