For more than 40 years, drivers in nearly every state have been allowed to turn right after stopping at a red light.

The Energy Policy and Conservation Act of 1975 mandated that states allow the maneuver as a gas-saving measure, provided it is safe to do so.

Drive reader Deb Stoll wondered about intersections such as Main Street and Hemlock Lane in Maple Grove, where there are two right-turn lanes.

"When there is more than one right-turn lane on a road, can a car from either/any of the right lanes turn right on a red light?" she asked in an email to the Drive. "I thought it was only the cars in the far right lane that could turn on red."

The short answer is yes, says Cmdr. Jonathan Wetternach of the Maple Grove police.

"A vehicle may turn right on red from either right-turn lane after coming to a complete stop, unless there is a sign indicating otherwise," he said. "Although right turns must generally be made as close as practicable to the right curb, the statute allows local jurisdictions to direct a different course of action through markers, buttons or signs."

But just because the turn is permitted by law, that doesn't mean drivers are required to proceed after stopping, though they may get honked at if they don't, said Matt Moseley, supervisor of driving programs for AAA Minneapolis.

"You don't have to take it," he said.

Double right-turn lanes add complexity and risk for drivers. Motorists in the lane closest to the curb should turn into the first available lane on the road they are turning onto. Drivers in the turn lane farthest from the curb should enter the lane or lanes farthest from the curb, Moseley said.

Problems and mishaps happen when drivers in turn lanes nearest the curb turn too wide and drift into the center or left lanes when entering the new road, thus cutting off other motorists, Moseley said.

Drivers making right turns on red must survey traffic from the left and also look for oncoming traffic making a left turn.

"We don't realize they have a green arrow," Moseley said.

Drivers making right turns on red must also yield to vehicles making a legal U-turn, another common mistake drivers make, Moseley said.

And they must scan multiple lanes of traffic to locate vehicles approaching the intersection and judge the speed of other vehicles to ensure there is a big enough gap to safely enter the road, Moseley said.

Before proceeding, turning drivers need to double-check their blind spot, he added.

"There may be a scooter, jogger or bicyclist that had not initially been there," he added.

The same rules apply to drivers making left turns from a one-way street onto another one-way street.

A recent report from Mineta Transportation Institute at San Jose State University found right turn on red movements are only marginally useful in lowering emissions and are generally unsafe for pedestrians, bicyclists and drivers because "most drivers do not come to a complete stop and instead roll through."

Minnesota law allows drivers to turn right on red unless a static or electronic "No Turn on Red" sign is posted. Mineta's report suggests laws be changed to ban the practice and let local jurisdictions decide on an intersection-by-intersection basis where the movement would be allowed.

"Sometimes it's just best to wait it out," Moseley said. "The light will turn green, and it will be much safer."