Simple, Low-Cost Changes Make Intersections Safer For Walkers

Inexpensive, low-tech safety features like bollards and rubber curbs installed on the yellow center line of roads at intersections can dramatically reduce close calls between left-turning vehicles and people on foot. The road design improvements make crosswalks safer by protecting people crossing the street the driver is turning onto, as left-turning vehicles pose considerable safety risks to walkers at intersections.  

Those are the highlights of a new study released on Thursday by the Insurance Institute for Highway Safety, a nonprofit financed by the insurance industry that looked at the impact of one type of traffic calming technique called “centerline hardening” that forces drivers to slow down when making left-hand turns and blocks them from cutting across intersections at a diagonal.

“This study suggests that simple infrastructure changes can deliver big benefits,”  Wen Hu, senior research transportation engineer for the Insurance Institute and lead author of the paper, said in a statement. “Communities looking for ways to make pedestrians safer should add centerline hardening to their toolbox.”

The report noted that pedestrian fatalities rose 53 % from 2009 to 2018 and currently account for about 17 % of traffic deaths nationwide.  In 2018, slightly more than half of all crashes involving pedestrians took place at intersections and left-turn crashes accounted for nearly a third of them.

To combat the problem, some cities have begun installing left-turn traffic-calming measures, including centerline hardening, at intersections. New York City has used these methods at more than 300 intersections since 2016. The District of Columbia began a similar effort in 2018, with plans to target 85 intersections by the end of this year. 

The study, “The effects of left-turn traffic-calming treatments on conflicts and speeds in Washington, D.C.,” examined how effective one type of centerline hardening  — the use of bollards and rubber curbs — was on the number of serious incidents between left-turning vehicles and people on foot and speed reduction. 

For the study, Hu collected data from intersections in Washington, D.C. before and after the infrastructure changes and compared them with control sites where no centerline-hardening features were installed.

The infrastructure changes resulted in a 70% reduction in the number of times drivers had to swerve or brake suddenly to avoid a pedestrian or a pedestrian had to stop short or dodge out of the way to avoid being hit by a vehicle during a left-hand turn. 

There was also a reduction in average vehicle speed when a driver completed a left-hand turn. 

The speed reduction was significant, as the odds of a walker sustaining a serious injury rise as the impact speed increases, even slightly, according to the report. 

“Our findings suggest that centerline hardening can be an effective tool,” alongside median islands and other measures, Hu added, “that have been demonstrated to reduce risks for the most vulnerable road user.”

For more information, click here and here.