Estimating the value of congestion under road pricing schemes

The answer to the environmental and economic problems that traffic congestion poses in large urban areas is often road pricing. While the literature about mode and route choice has focused on the value of congestion and the literature about road pricing has focused on economic aspects of road pricing, a missing link is the evaluation of congestion under road pricing schemes. Accordingly, this study contributes to the literature by estimating the value of congestion of drivers under road pricing schemes from a route choice experiment. The experiment was performed in Copenhagen, where GPS devices traced the trips of 240 drivers that were assigned to three groups. Each group drove without any pricing scheme and either (i) a cordon toll scheme, (ii) a low pay-per-km scheme, or (iii) a high pay-per-km scheme. The GPS traces were map-matched, choice sets were generated, and mixed logit models were estimated to evaluate the value of congestion as the ratio between the parameters for congested and free flow travel time. Results show that higher heterogeneity was observed for the cordon toll and the low pay-per-km schemes, but also that the value of congestion not only increases significantly under road pricing schemes, but also reaches the highest values when a cordon toll pricing scheme is imposed.