Bereft from Left

 

   Slow Turn Wedge in NYC       San Francisco’s approach

Traffic accidents kill about 30,000 Americans every year, the eighth leading cause of death in the nation. “Every year, the Federal Highway Administration (FHA) reports approximately 2.5 million intersection accidents. Most of these crashes involve left turns… Nationally, 40 percent of all crashes involve intersections, the second largest category of accidents, led only by rear-end collisions. Fifty percent of serious collisions happen in intersections and some 20 percent of fatal collisions occur there.” AutoAccident.com, March 31st. Pedestrians have the greatest risk.

According to an April 9, 2020 publication from the Insurance Institute for Highway Safety, “A little more than half of all crashes involving pedestrians took place at intersections in 2018, resulting in more than 6,700 serious injuries to pedestrians and more than 1,500 pedestrian fatalities. In one of the more common scenarios, a driver making a left turn crashes into a pedestrian crossing the road the driver is turning onto. These left-turn crashes accounted for nearly a third of all pedestrian-involved crashes at intersections in 2018.

“To combat the problem, some cities have begun installing left-turn traffic-calming measures at their intersections. New York City has used these methods at more than 300 intersections since 2016. The District of Columbia began a similar effort as part of its Vision Zero program in 2018, with plans to target 85 intersections by the end of this year. One turn-calming technique the city uses is centerline hardening, which consists of rubber curbs and bollards installed on the yellow center line.” Portland, Oregon is also focused on this issue.

A more detailed examination of one city’s approach, San Francisco, illustrates this nationwide reality. Nate Berg, writing for the December 6th FastCompany.com, explains: “Drivers turning left are responsible for a disturbingly high proportion of pedestrian injuries and deaths in the city of San Francisco. Solving the problem could be a matter of design… More than 300 people are injured by left-turning drivers every year in San Francisco. In 2019, 40% of traffic deaths occurred when drivers making left turns hit pedestrians – mostly people using crosswalks who weren’t seen by drivers until it was too late. Now, the city is dramatically rethinking its intersections to make these dangerous left turns a thing of the past.

“The scope of the problem became evident back in 2018, when the San Francisco Department of Public Health analyzed five years’ worth of left-turn crash data. The agency then teamed up with the San Francisco Municipal Transportation Agency (SFMTA) to better understand why so many deaths were happening in left turn situations. What they found was a mix of design issues and common driver behaviors that unnecessarily put pedestrians at risk. To address both of these problems, SFMTA launched the Safer Intersections Project to test out new approaches to intersection design, as well as a $2 million grant-funded public education campaign aimed at reducing unsafe driving. The effort is part of the city’s Vision Zero plan, which aims to eliminate traffic-related deaths…

“On the design side, the agency found that part of the reason left turns are so dangerous is that drivers are often going too fast and turning at too tight of an angle to properly see whether a pedestrian might be crossing the street. This has deadly consequences, particularly for older people, who make up 31% of pedestrians killed in left turn situations.

“The intersection retrofits are aimed at changing the way drivers navigate during left turns, and include the placement of vertical posts partly inside intersections, six-foot rubber speed bumps that extend the centerline of travel lanes, and large painted zones that show drives where not to drive. These physical elements force drivers to slow down and make more of a right-angle turn through the intersection as opposed to a fast swooping curve. By making it harder to turn quickly, drivers have more time to see people crossing the road.

“The design interventions were installed at seven intersections in the city last fall. After a year of monitoring, SFMTA has found that the altered intersections have had significant impacts on the speed and safety of left turns. The interventions reduced the average speed at which drivers make left turns by 17%, and brought a 71% reduction in drivers taking turns faster than 15 miles per hour. More data will be collected to see whether these interventions result in reduced collisions, injuries ,and deaths.

“The interventions are focused mostly on intersections with traffic signals. Though signaled intersections make up only 13% of the city’s intersections, they are where two-thirds of all left turn collisions occur.” Additionally, a public relations campaign is attempting to inform drivers of the risks. There has been a particular focus on locations with existing high left-turn speeds, conducive street geometry, and lots of people walking and biking. The main thing is that this approach actually works, and until automotive engineering takes the driving away from human beings, this is a reasonable solution to intersection accidents.

I’m Peter Dekom, and sometimes looking at the obvious and dealing with it in an obvious manner eludes too many urban planners.