Effects of a mileage tax for trucks

We evaluate the effect of the introduction of a mileage tax for trucks in Switzerland in 2001 on traffic volume and externalities. Using a regression discontinuity design, we find a reduction in overall truck traffic of around 4–6%, no effects on car traffic and time-shifted placebos, suggestive evidence for traffic substitution toward rail, and negative effects on nitrogen oxides at curbside monitors. Complementary estimates on the effects of the German mileage tax and complementary estimates based on the synthetic control method are broadly consistent with our main results, although the latter are not statistically significant. Depending on prevailing levels of transportation costs, mileage tax-induced transportation cost increases may accelerate or reverse spatial economic concentration processes. Such implications for economic geography featured prominently in Switzerland and are a promising area for future research.