The most dangerous turns in town
Understanding the risks posed to pedestrians and cyclists by left-turning vehicles — and what the city is doing about it
Shortly before 6 a.m. on the morning of Feb. 4, Joseph Chiam, a 72-year-old East Village resident, was riding his bicycle north on Eighth Avenue when he was struck and killed by a commercial truck near West 45th Street.
The circumstances of the fatal collision were familiar to observers of New York City transportation safety policy.
The driver of the truck — who fled the scene and, more than a month later, has not been arrested — was also heading north on Eighth Avenue, and hit Chiam while turning left onto West 45th Street.
Chiam was at least the fifth cyclist or pedestrian killed by a left-turning vehicle in Manhattan in the last six months, and one of at least 16 left turn fatalities citywide over the same period.
A 2016 study conducted by the city’s Department of Transportation found that left-turning vehicles cause a disproportionate share of pedestrian and cyclist fatalities and injuries in New York City. The study indicated that 108 pedestrians and cyclists were killed by left-turning vehicles between 2010 and 2014 — accounting for more than one of every eight fatalities and more than a quarter of all injuries suffered by pedestrians and cyclists during the period. Left turns result in fatalities and severe injuries at three times the rate of right turns, the DOT found.
Transportation planners attribute the so-called “left turn problem” to confluence of factors.
Speed is a key issue: drivers tend to go faster turning left than when they turn right. When turning onto a two-way street from a one-way street, for instance, a driver turning right is forced to turn at a tight radius, which necessitates a slower speed. By contrast, drivers turning left often “cut the corner” across the double-yellow line, which in addition to allowing for higher speed also creates a larger zone of potential conflict with cyclists and pedestrians.
A driver’s field of vision is also diminished during a left turn. The blind spot created by the portion of the vehicle frame between the windshield and the driver’s side window can often obscure passing cyclists or pedestrians in the crosswalk.
These risk factors are compounded further on two-way streets without dedicated left-turn signals, where drivers must time their turn to a gap in oncoming traffic and deal with so-called “back pressure” from trailing vehicles — potentially drawing their attention away from bikers and pedestrians in their path as they commit to the turn.
These dangers are a factor in UPS’s longstanding policy of routing drivers to avoid left turns unless they are unavoidable. The company has also found that it saves time and fuel.Left turn “calming treatments”
As traffic deaths in New York City have reached historic lows in recent years (in spite of an uptick last year in pedestrian deaths), the city has prioritized improving dangerous left turn intersections as part of its Vision Zero street safety program.
Since 2016, the DOT has installed low-cost treatments designed to reduce left turn speeds at more than 300 high-risk intersections citywide, including over 125 in Manhattan. These left turn traffic “calming treatments” vary by intersection configuration, but often include plastic bollards or rubber curbs intended to force cars to turn at a tighter radius, resulting in slower speeds.
According to the DOT, pedestrian injuries have dropped more than 20 percent at intersections that have received these treatments, outpacing injury reduction rates at comparable locations. Vehicle turn speeds have also dropped about 20 percent.
Additionally, the Taxi and Limousine Commission now emphasizes left turn safety in its drivers’ video training, and the Metropolitan Transportation Authority is currently exploring improved bus designs to enhance the bus operator’s view when making left turns.
The DOT plans to install left turn traffic calming treatments at another 100 intersections in 2019. A spokesperson said specific locations will be released in the coming months.
Meanwhile, many dangerous left turns along Vision Zero priority corridors such as Eighth Avenue remain without calming treatments, including the West 45th Street intersection where Chiam was killed. At that intersection, vehicles use a turning lane adjacent to the curbside bike lane, and must account for passing cyclists as they cross the bike lane to turn left.
Joseph Cutrufo, communications director with the bicycle and pedestrian advocacy group Transportation Alternatives, said that such mixing zones inevitably put cyclists in danger.
“When we have to rely on drivers to protect cyclists, that’s clearly a flaw in the system,” Cutrufo said. “We can’t leave it up to drivers to keep cyclists safe. We need the design of the streets to do that.”
At some similar intersections, DOT has implemented a treatment known as a slow turn wedge. These wedges, consisting of plastic bollards or rubber speed bumps extending from the corner of the curb, force drivers to turn at a tight radius, increasing driver’s visibility of cyclists and pedestrians heading in the same direction as the car.
“I would hate to see the city wait for more cyclists to be killed or maimed before they start installing these en masse,” Cutrufo said.
Another available option is the split-phase traffic signal configuration, which holds left-turning vehicles at a red light while allowing pedestrians and bicycles cross with their own green light, eliminating the conflicts created by mixing zones.
Transportation Alternatives is also lobbying for automated camera enforcement of blocking the box and failure to yield violations.
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