Intervention analysis of the safety effects of a legislation targeting excessive speeding in Canada.

Excessive speeding is a major traffic safety concern consequently, numerous countermeasures have been considered to mitigate this problem. Excessive speeding, street racing and stunt driving activities subject all road users to extreme risk. To address this problem, three Canadian provinces introduced severe sanctions against drivers who exceed speed limits by high margins. Under the laws offenders were subject to immediate license suspension and vehicle impoundment. In this paper, intervention analysis of the collision data from the three provinces was conducted to identify the safety effects of the legislation. The analysis aims to identify changes in the time series behaviour of collision data after the adoption of the law. The changes were assessed for statistical significance, and the magnitude of the change was quantified. In general, the paper showed that the legislative changes were associated with drops in province-wide fatal collisions substantiating the safety benefits of introducing such legislation against excessive speeders.