TORONTO–Speed-related, at-fault collisions involving large commercial vehicles fell by a whopping 73-percent after mandatory speed-limiter legislation took effect in Ontario, according to a recent study by the Ontario Ministry of Transportation. The drop in truck collisions was significantly greater than the decrease found in other vehicle drivers (30%).

Despite skeptics’ insistence before the rule took effect that slowing down large trucks would inadvertently lead to more collisions with passenger cars and other vehicles, the study concluded there is absolutely no evidence speed limiters have contributed to an increase in truck drivers involved in other types of collisions post-2009, including rear-end crashes.

Moreover, the study also dispelled the myth that in a speed-limiter environment, drivers adjust their driving behaviour to compensate for any perceived time lost as a result of driving slower.

The year-long study conducted between 2014-2015 examined data from pre- (2006-2008) and post- (2010-2012) speed-limiter legislation by using fatal, injury and police reported property damage collisions on high-speed highways. It also looked at MTO enforcement officers’ large vehicle driver speed data, among other real-world data.

The Ontario Trucking Association (OTA), a strong proponent of mandatory speed limiters, worked closely with the Ontario government at the time to get the rule enacted. 

Additional highlights from the study:

• Drivers of large trucks produced fewer at-fault speed collisions relative to all at-fault driver actions, post 2009;
• No evidence to indicate worse collision outcomes for large truck drivers post 2009;
• The percentage of truck drivers struck in the rear (of all collisions), stayed the same from pre- to post legislation (10.03 % of total collisions 2006-2008 and 10.47% 2010-2012) while the rate increased for other drivers (18.6% 2006-2008; and 21.3% 2010-2012).

Going forward, the study suggests some recommendations to raise compliance and realize the full benefits of the speed limiters, including increased enforcement and enhancing the electronic control module (ECM) technology readers available to enforcement to scan and display a wider array of engine parameters.