CHARLOTTE, N.C. — When the city of Cornelius floated the possibility of eliminating left-turn lanes at certain intersections, it brought up questions about the effect these designated turn lanes have on traffic and safety as a whole.
THE QUESTION
Does restructuring left-turn lanes in some areas reduce traffic congestion?
THE SOURCES
THE ANSWER
Yes, restructuring left-turn lanes in some areas can reduce traffic congestion. Especially in areas of heavy congestion, said Epperson, "like your major roadways."
Gayah said reformatting intersections with alternatives to left turns is part of future transportation plans in major cities like Charlotte, because traffic is only going to get worse with more and more people moving to urban areas.
WHAT WE FOUND
Many civil engineers have studied the impact of different street network designs and how they might influence traffic.
Gayah recently published a study about what would happen if left turns were eliminated in certain parts of urban areas.
Gayah found that in general, left turns are pretty dangerous.
"The way we serve left turns in traffic is we either allow the driver to make the decision on when to turn left, so sort of look for gaps in the opposing traffic, and make that maneuver," Gayah said. "And, of course, you know, if the driver makes an error in judgment, that leads to a crash. And those types of crashes tend to be, you know, pretty, pretty catastrophic."
Gayah's study also highlighted how in some cases, left-turn lanes can be inefficient and cause traffic congestion at intersections.
According to data from NCDOT, urban areas will benefit from different solutions to left-turn lanes, such as roundabouts, U-turns, or side street right turns. These are called reduced conflict intersections.
"So typically, if we redirect that left turn, you do travel further, but during your busier times of the day, in most cases actually takes you less time to get back to where you were trying to get to. Because there's less congestion," Epperson said.
VERIFY is dedicated to helping the public distinguish between true and false information. The VERIFY team, with help from questions submitted by the audience, tracks the spread of stories or claims that need clarification or correction. Have something you want VERIFIED? Text us at 704-329-3600 or visit /verify.