Road Safety Impact of Increased Rural Highway Speed Limits in British Columbia, Canada

Jeffrey Brubacher,Herbert Chan,Shannon Erdelyi,Farhad Faghihi,Gordon Lovegrove

doi:10.3390/su10103555

Jeffrey Brubacher, Herbert Chan + Show 3 more

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https://doi.org/10.3390/su10103555

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Abstract

Control of vehicle speed is a central tenet of the safe systems approach to road safety. Most research shows that raising speed limits results in more injuries. Advocates of higher speed limits argue that this conclusion is based on older research, that traffic fatalities are decreasing despite higher speed limits, and that modern vehicles are able to safely travel at higher speeds. These arguments were used to justify raising speed limits on rural highways in British Columbia, Canada (July 2014). We used an interrupted time series approach to evaluate the impact of these speed limit increases on fatal crashes, auto-insurance claims, and ambulance dispatches for road trauma. Events were mapped to affected road segments (with increased speed limits) and to nearby road segments (within 5 km of an affected segment). Separate linear regression models were fitted for each outcome and road segment group. Models included gasoline sales to account for changes in vehicle travel. Our main findings were significant increases in (i) total insurance claims (43.0%; 95% Confidence Interval [CI] = 16.0–76.4%), (ii) injury claims (30.0%; 95% CI = 9.5–54.2%), and (iii) fatal crashes (118.0; 95% CI = 10.9–225.1%) on affected road segments. Nearby segments had a 25.7% increase in insurance claims (95% CI = 16.1–36.1%).

Highlights

Road trauma is a global public health problem that results in over 3000 deaths per day [1]
We studied adverse motor vehicle incidents (MVIs), including ambulance calls for road trauma, auto-insurance claims, and police-reported crashes occurring on the affected road segments
There were no other statistically significant changes on nearby segments, but it is worth noting that the point estimate for change in fatal crashes on nearby segments was −46.7%

Summary

Introduction

Road trauma is a global public health problem that results in over 3000 deaths per day [1]. Moving vehicles are the source of kinetic energy (EK) that causes injury in motor vehicle crashes (MVCs) and the phrase “speed kills” highlights the central role of vehicle speed in road trauma. Higher speed means more EK and more severe injury in event of a crash, regardless of the cause. Higher travel speeds make the task of driving more difficult, because drivers must perceive, interpret, and respond to relevant stimuli at a faster rate. Even when the driver perceives a hazard and responds appropriately, higher speed results in greater distance travelled by the vehicle during perception and reaction times [5], and in exponentially greater braking distance [6]. Higher speeds make it more difficult to negotiate curves or manoeuver around road hazards, and faster vehicles are more difficult for other road users to avoid

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