Drivers will test a new way of turning left at busy intersections in Cary and Clayton
Drivers at a busy intersection in Cary will soon encounter an experiment in managing left turns that is designed to improve the flow of traffic.
The N.C. Department of Transportation calls it a “dynamic left turn,” because it involves using both left-turn lanes during busy times but restricting left turns to one lane at others. NCDOT says it will also try the idea at an intersection in Clayton later this spring.
The new concept is scheduled to go live Tuesday, Feb. 11, for drivers making left turns from eastbound Tryon Road onto Southeast Cary Parkway toward the U.S. 1/64 interchange. During rush hour and other busy times, both left turn lanes will be open as they are now, and drivers will turn only on a green arrow, while oncoming traffic is stopped.
But at other times, the right-hand left-turn lane will be closed, with a red X on two lit signs hanging overhead warning drivers to stay out of it. Drivers in the left-hand turn lane will be given a flashing yellow arrow, allowing them to turn when there are breaks in oncoming traffic. Occasionally, the oncoming traffic will get a red light to allow several cars to make a left turn at once on a green arrow.
The idea is to reduce the amount of time that through traffic must come to a stop to allow left turns, according to Joe Hummer, NCDOT’s traffic management engineer.
“We are using standard devices to reduce travel delays in a novel way,” Hummer said in a written statement. “We are basically freeing up this intersection to give more green time for people going straight through it.”
In Clayton, NCDOT will install a dynamic left turn for drivers from westbound U.S. 70 Business turning into Town Centre Boulevard and the Walmart store this spring.
Hummer says the idea came from Joe Milazzo, who heads the Regional Transportation Alliance, a program of the Greater Raleigh Chamber of Commerce. Milazzo, a civil engineer, said he’s not aware of this kind of approach being used anywhere else in the country and that it should reduce the amount of time drivers at these intersections sit at red lights.
“To be clear: nothing at a dynamic left turn intersection is ‘new’ — everyone has seen dual left turn lanes, an overhead ‘X’ lane control signal like they have by PNC Arena, a flashing yellow arrow, etc.,” Milazzo wrote in an email. “What is new is this particular combination of intersection elements, that will allow the intersection to operate more efficiently throughout the day.”
NCDOT says it will monitor both intersections to make sure drivers adjust to the new way of turning left and will evaluate whether it is achieving its goals. If it works, the department says it may install dynamic left turns in other places in the future.
