Yellow left-turn signals get their chance to shine

1:10 PM, Jun 16, 2011   |    comments
States are increasingly installing yellow flashing left turn signals at busy intersections.
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Tired of waiting to make a left turn at a busy intersection? A growing number of states have decided there's a better way to make those turns that keeps traffic moving, increases safety and reduces gasoline consumption.

The solution: adding a flashing yellow arrow to traffic lights.

The Federal Highway Administration estimates that the signals - which allow drivers to make a left turn after yielding, even when the light is red for traffic going straight and opposing traffic has a green light - are in use at more than 1,000 intersections, and the number is rising, spokeswoman Cathy St. Denis says.

"I don't even think you can quantify how many have been installed in the past six months, because the installations are happening so rapidly," says David Noyce, a researcher at the University of Wisconsin. "We are approaching where either every state has implemented it or is thinking about it."

St. Denis says research shows that drivers making a left turn can too easily misinterpret a green signal as giving them the right of way. "A flashing yellow arrow is more easily understood as meaning 'look for and yield to oncoming traffic before you turn left,'" she says.

Noyce says left-turn accidents have dropped where the lights have been installed.

Margaret Fuqua of the Kentucky Transportation Cabinet says it's early for a thorough evaluation because of the short time span and limited number of installations, but so far, there has been about a 30% reduction in left-turn collisions.

The first signal in east central Florida was installed Monday in Palm Coast. As many as 30 more are planned, Florida Department of Transportation spokesman Steve Olson says.

Flashing yellow arrows are now in San Antonio, Minneapolis, St. Paul, Seattle and Detroit, among other cities, St. Denis says. This signal is the standard for intersections in states including Florida, Oregon and Minnesota, says Mike Knodler, associate professor at the University of Massachusetts-Amherst.

The lights haven't worked everywhere. In Washington County, Ore., a signal was removed from an intersection in 2009 after eight crashes were reported within two years, county spokesman Stephen Roberts says. "We will err on the side of safety over efficiency," he says.

Natalie Diblasio, USA TODAY

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