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- Jun 27, 2011
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(CNN)UPS trucks almost never take left-hand turns.
By favoring right-hand turns at all times -- unless a left is unavoidable -- the carrier saves millions of gallons of fuel each year, and avoids emissions equivalent to over 20,000 passenger cars.
The practice started decades ago, before computers and GPS, and is now managed by a software that conjures the most efficient route for each truck.
What's wrong with turning left?
Left-hand turns are generally considered unsafe and wasteful on right-hand driving roads, such as those in the US.
"Left-turning traffic typically has to turn against a flow of oncoming vehicles," explains Tom Vanderbilt, author of the book "Traffic: Why we drive the way we do."
"This can not only be dangerous, but makes traffic build up, unless you install a dedicated left-turn 'phase,' which is fine but basically adds 30 or 45 seconds to everyone else's single time," he said.
A study on crash factors in intersection-related accidents from the US National Highway Traffic Safety Association shows that turning left is one of the leading "critical pre-crash events" (an event that made a collision inevitable), occurring in 22.2 percent of crashes, as opposed to 1.2 percent for right turns. About 61 percent of crashes that occur while turning or crossing an intersection involve left turns, as opposed to just 3.1 percent involving right turns.
Left turns are also three times more likely to kill pedestrians than right ones, according to data collected by New York City's transportation planners.
By favoring right-hand turns at all times -- unless a left is unavoidable -- the carrier saves millions of gallons of fuel each year, and avoids emissions equivalent to over 20,000 passenger cars.
The practice started decades ago, before computers and GPS, and is now managed by a software that conjures the most efficient route for each truck.
What's wrong with turning left?
Left-hand turns are generally considered unsafe and wasteful on right-hand driving roads, such as those in the US.
"Left-turning traffic typically has to turn against a flow of oncoming vehicles," explains Tom Vanderbilt, author of the book "Traffic: Why we drive the way we do."
"This can not only be dangerous, but makes traffic build up, unless you install a dedicated left-turn 'phase,' which is fine but basically adds 30 or 45 seconds to everyone else's single time," he said.
A study on crash factors in intersection-related accidents from the US National Highway Traffic Safety Association shows that turning left is one of the leading "critical pre-crash events" (an event that made a collision inevitable), occurring in 22.2 percent of crashes, as opposed to 1.2 percent for right turns. About 61 percent of crashes that occur while turning or crossing an intersection involve left turns, as opposed to just 3.1 percent involving right turns.
Left turns are also three times more likely to kill pedestrians than right ones, according to data collected by New York City's transportation planners.
