The research is clear; left turns are generally dangerous for all motorists — and pedestrians. According to a study by New York City’s transportation planners, left-hand turns were three times as likely to cause a deadly crash involving a pedestrian as right-hand turns. Drivers turning left accounted for 19 percent of serious pedestrian and bicyclist injuries in New York City.
According to a study by the National Highway Traffic Safety Association (NHTSA), turning left is one of the most common pre-crash events, occurring in 22 percent of crashes, as opposed to 1.2 percent for right turns. About 61 percent of crashes that occur while crossing an intersection or turning involve left turns, as opposed to 3.1 percent involving right turns. The NHTSA also found that 36 percent of fatal accidents involving a motorcycle involved a left-hand turn in front of a motorcycle. Traffic engineers also claim that left-hand turns can cause congestion, further increasing the risk of accidents.
Vehicles turning left have to turn against the flow of oncoming cars, which some say is dangerous and builds up traffic. In fact, the parcel delivery company UPS instructs its drivers to almost never take left-hand turns, which the company claims saves millions of gallons on gas each year due to decreased time waiting in traffic. The company’s software determines the most efficient route for each truck, and generally that route avoids left turns. One UPS employee explained that when a motorist makes left turns, their car has to idle longer, which burns fuel.