Accident externalities that individual drivers impose on one another via their presence on the road are among the most important external costs of road transport. We study the regulation of these externalities when insurance companies have market power. Some of the results we derive have close...

In most dynamic traffic congestion models, congestion tolls must vary continuously over time to achieve the full optimum. This is also the case in Vickrey (1969) ‘bottleneck model’. To date, the closest approximations of this ideal in practice have so-called ‘step tolls’, in which the...