Why Left Turns Are So Deadly

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A car turns left in Manhattan as pedestrians cross the street.

One of the most challenging maneuvers for a driver to make — a left turn — is also one of its most dangerous for pedestrians.

Park Slope resident Emily Miller learned that first-hand. On the day before Thanksgiving last year, she was doing some last-minute food shopping not far from her home. She waited for the walk light at the corner of Fourth Avenue, a busy thoroughfare, and Third Street, a side street. Then she stepped out to cross Third Street.

She was struck by a car making a left turn from Fourth Avenue.

"I heard a thud," she said, "and I felt myself traveling through space. And the next thing I remember was being on my back and pretty quickly being surrounded by a good number of people."

One of them was the driver of the car that hit Miller, a woman in her 20s. Distraught, the woman jumped out of her car.

"She started to cry," said Miller, "and hold my hand."

Miller was taken to the hospital, where she spent the next two and a half weeks recovering from a broken leg, a banged-up arm, a concussion and a punctured lung. She’s still in physical therapy. The police report assigns no blame, saying only, "All traffic devices were obeyed."

That is one of the biggest problems with left turns. The turning driver has a green light right when pedestrians have the walk light. But it is not the only issue.

Anne McCartt, senior vice president for research at the Insurance Institute for Highway Safety, says left turns are tricky because drivers must make a complex series of judgments in a short period of time. Is the light about to turn? Are all the oncoming lanes clear? And why is the guy behind me honking?

(The entire experience of making lefts can provoke serious driver anxiety, as evidenced by a number of threads on different support forums.)

"You have to try to gauge the speed and distance of oncoming vehicles," she said. "And a problem at intersections is that people often speed through the light."

That acceleration is one of the reasons left turns are more deadly for pedestrians than right turns.

For drivers, that split-second decision-making workout is called the driver workload, according to Jeff Shaw, the intersections program manager for the Federal Highway Administration's Office of Safety.

"The more and more a driver has to process, the more likely it is a mistake could be made," he said.

And there's another piece of the equation: vehicle A-pillars. Those are the front pieces of the car frame; they hold the windshield in place and support the roof. They have to be strong enough to withstand rollover, and they also often house airbags. And as crash standards have evolved over the years, so has the size of the front pillars.

"When we compare the data, we find that drivers could see more outside their vehicles in the 1980s than they can now," Dr. Matthew Reed, a research professor with the University of Michigan's Transportation Research Institute, said.

Reed said it is difficult to quantify how many crashes are caused by A-pillar obstruction. But, he said his research showed, "the type of crash that’s most influenced by pillar width are crashes with pedestrians. Our hypothesis is that drivers can’t see as well out of the vehicles that have wider pillars. And that puts pedestrians at risk."

The European Union mandates the amount of visibility a driver must have. By contrast, the U.S. does not regulate the characteristics of A-pillars.

To really understand how it works, Reed suggested I sit in the driver's seat of a car and have someone walk in a circle outside it. "You might be surprised by how many different locations they could stand without you being able to see them very well," he told me.

I took Reed's advice, and had my daughter walk around my parked car while we were in an empty lot. And, as Reed had predicted, there was moment where she was completely blocked by the A-pillar. Watch her walk in and out of my field of vision below.



According to WNYC data, 17 pedestrians and three cyclists were fatally struck by vehicles making left turns last year. In fact, New York has the highest number of pedestrian fatalities caused by left-turning vehicles of any state in the country, according to federal statistics (see below PDF.) And a recent city Department of Transportation presentation stated that left turn crashes outnumber right turn crashes 3 to 1.

For the past few years, the city’s Department of Transportation has been redesigning dozens of intersections to make left turns safer. But at a hearing in March, Transportation Commissioner Polly Trottenberg told City Council members there are limits to what can be done.

"Left turns are a big source of crashes," Trottenberg said. "But there's another way to look at it: speeding and failure to yield, which are also pieces of the puzzle, are also sources. There's no question, in cases where we can minimize left turns, or give vehicles their own turning phase, we want to try to do that."

She added, however, "We won't be able to do it everywhere in the city. You can't create a special turning lane and a special signal in every intersection for left turns."

Even those measures don’t guarantee safety. The Brooklyn intersection where Emily Miller was struck has both a turning lane and a dedicated traffic signal. In fact, Fourth Avenue is so dangerous it is one of four city streets slated to receive a massive safety overhaul.

United Parcel Service has another way to deal with left turns: just don't do them.

UPS plots its delivery routes in a right-turning loop, because the company does not want its drivers to waste time and gas waiting for a gap in oncoming traffic.

Dan McMackin, now a spokesman for UPS, got his start with the company driving a truck. The habits he picked up then are ingrained in his routine now.

Most weekends, he said, take him to Home Depot, Starbucks, CVS Pharmacy and a BP gas station.

And he's plotted out his route to eliminate left turns altogether.

"Because I make a right hand turn to go to Home Depot after I go to Starbucks, I probably save about eight minutes off my total route."

It's probably safer, too.

Ped Fatalities by State by Precrash Vehicle Manuever 2010-2013 (2)