Depowering Risk: Vehicle Power Restriction and Teen Driver Accidents in Italy

This paper investigates how a vehicle power limit on young novice drivers impacts teen traffic accidents in Italy. First introduced in 2011, the reform prevents drivers from using high-performance vehicles during their first license year. We combine rich administrative data on severe accidents over the period 2006-2016 with the driving license census to assess whether undergoing the power limit lowers the likelihood of causing a traffic accident. Our difference- in-difference estimates – we leverage on the between-cohort differences in the exposure to the reform – reveal that the power limit reduces road accidents per capita by about 18%, and accidents per licensee by 13%. The effect is entirely determined by a drop in accidents caused by above-limit vehicles and is primarily driven by fewer speed violations. Moreover, the beneficial impact of the one-year restriction period persists even after its expiration. Our findings highlight the importance of policies that, instead of directly targeting risky behaviours, are aimed at reducing exposure to high-risk settings. In frameworks where deterrence policies and screening mechanisms are hard to implement and maintain, these policies stand out as an effective, yet feasible strategy to increase teen road safety.