Road traffic regulation: road pricing and environmental quality

This chapter discusses the empirical literature on the effectiveness of road pricing in curbing pollution, by discussing regression discontinuity design in time series with thresholds centered on the dates of the introduction of the charge. With specific reference to the London Congestion Charge a negligible and adverse impact of the charge is documented. These findings are consistent with an overal increase in traveled kilometers, due to traffic diversion from the charged to the uncharged area. Furthermore, there is an unclear, possibly adverse, impact of increased speed on pollution.