No. Road design is equally relevant
Frequent pedestrian and cyclist deaths in Toronto have raised concerns about improving road safety. The city adopted Vision Zero as a policy response, though safety metrics have not improved subsequently.
Many proponents of safer streets call for lowering traffic speeds. Collisions between motorized vehicles and pedestrians or cyclists at lower speeds are known to cause less severe injuries and fewer fatalities than collisions at higher speeds.
However, empirical evidence that would demonstrate that the lowering of speeds on specific urban roads results in improved pedestrian safety is either missing or inconclusive.
Most research on the impact of speed limits on pedestrian safety is either based in rural settings or is cross-jurisdictional rather than before-and-after studies of the same urban road segments.
Equally relevant is the consideration that lowering speed limits alone is unlikely to alter driver behaviour if it is not accompanied by introducing traffic calming devices or reducing lane widths.
The design speed of the road segment and not just the posted speed limit determines driver behaviour. For instance, Harris County in Texas ended up reinstating higher speed limits on freeways after the county realized that lower speed limits introduced in mid-2000 did not reduce operating speeds.
Whereas traffic safety, when proxied by the total number of fatalities, has improved over the years, the same is not necessarily true for pedestrians. In the U.S., traffic deaths have declined by 14 per cent from 2007 to 2016.
However, during the same time, pe- destrian deaths increased by 27 per cent, reaching 6,000 in 2017.
The causes behind the increase in pedestrian fatalities in the U.S., or in Toronto, are not known for certain.
A recent report by the Governors Highway Safety Association speculates that the legalization of cannabis and increased prevalence of cellphones are correlated with the increase in pedestrian fatalities. Also, the pedestrian death toll is larger in sunbelt states, including Arizona, California, Florida and Texas.
Toronto became a Vision Zero city in June 2016 with the aim to improve the safety of pedestrians and cyclists. Yet the safety statistics do not reveal a noticeable decline in either fatalities or injuries of nonmotorized road users.
Toronto is not the only Vision Zero city that has not seen an improvement in pedestrian safety. Los Angeles, another Vision Zero city, saw a huge spike in pedestrian deaths, reaching 134 in 2017. In Toronto, the combined toll for pedestrian and cyclist deaths has averaged around 40.
Prof. Bhagwant Persaud of Ryerson University is an expert in safety engineering. He points out that when traffic calming devices are placed on some road segments, traffic might migrate to other non-calmed streets, thus shifting the problem from one part of the road network to another.
In the fall 2009, Montreal lowered speed limits from 50 to 40 km/h on local streets. A retrospective analysis of the intervention showed that while occurrences of speeding (50 km/h) were reduced, the intervention was not effective with excessive speeding of 80 km/h or higher.
While traffic calming interventions are generally effective, their placement and type require due consideration. Prof. Dominique Lord, an expert in traffic safety at the Texas A&M University, cautions that traffic calming devices, such as curb extensions and road humps, may not be placed on arterials or collectors, but instead on local urban roads. He further suggests that 10-footwide lanes are more effective in lowering speed limits than the 12-foot-wide lanes.
As part of Vision Zero initiatives, Toronto should consider implementing proper engineering pilot studies where speed limits are reduced on carefully selected road segments while they are not altered on other control segments that are identical in all aspects except the difference in speed limits.
Safety outcomes compared before and after the changes in speed limits between treated and control road segments will help advance our understanding of what interventions work in improving the safety of pedestrian and cyclists in urban contexts.