Objective To assess the effect on collisions with injuries of a 61% reduction in the number of traffic citations issued by police officers over a 21-month period.

Methods Using descriptive analyses as well as ARIMA intervention time-series analyses, this study estimated the impact of this reduction in citations issued for traffic violations on the monthly number of collisions with injuries.

Results Simple descriptive analysis reveals that the 61% reduction in the number of citations issued for traffic violations during the experimental period coincided with an increase in collisions with injuries. Results from the interrupted time-series analyses reveal that, on average, eight additional collisions with injuries occurred every month during which the number of tickets issued for traffic violations was lower than normal. As this pressure tactic was applied for 21 months, it is estimated that this situation was associated with approximately 184 additional collisions with injuries: equivalent to 239 traffic injuries (either deaths, minor or serious injuries).

Conclusion In the province of Quebec, police officers are an important component of road safety policy. Issuing citations prevents drivers from adopting reckless driving habits such as speeding, running red lights and failing to fasten their seat belt.