From Track to Traffic: A Natural Experiment on Speed Contagion Following Montreal’s F1 Grand Prix

Major sporting events may influence traffic safety by affecting driver behavior and collision risk. We examined whether the Montreal Formula 1 Canadian Grand Prix weekend was associated with changes in high-speed motor vehicle collisions in Quebec (2000-2022). Using a space-time-stratified case-crossover-control design, we analyzed police-reported speeding collisions in host (Montreal, Laval, Longueuil) and non-host municipalities (Quebec City, Sherbrooke). The exposure window was Thursday-Sunday of race weekend vs. the same weekdays two weeks earlier, with 2-day lagged outcomes (i.e., Saturday-Tuesday). Conditional quasi-Poisson regression estimated rate ratios (RR), adjusting for temperature and precipitation. Host municipalities showed increased high-speed collisions (RR= 1.37; 95% CI: 1.12-1.69), resulting in 82 cumulative excess collisions (95% CI: 40-133), or four per event, whereas non-host municipalities showed no change (RR= 1.01; 95% CI: 0.71-1.42). The host vs. non-host municipality-years comparison yielded a consistent but less precise relative rate ratio (1.36; 95% CI: 0.91-2.04). Limitations include sparse data, small geographical-year units, and the inability to distinguish motorsport-specific from large-event effects. Our findings partially support the hypothesis that speed contagion contributes to collisions during Formula 1. Imprecise estimates warrant higher-resolution analyses with additional case studies.