The state Department of Transportation plans to install traffic signals on four on-ramps on Interstate 540 in Raleigh early next year to break up the long lines of vehicles that pour onto the freeway during rush hour.
The signals, known as ramp meters, will switch between green and red, allowing one or two drivers to go, then stopping the next ones for a few moments. The idea is that putting some space between the vehicles on the ramp should make it easier for them to merge into traffic on the highway.
“That translates to better traffic flow and more reliable times on the freeway, as well as improved safety and fewer crashes,” said Kevin Lacy, DOT’s state traffic engineer.
It will be the first time ramp meters have been used in North Carolina, though they’re common in other large cities, including New York, Houston and Atlanta. They’ve been used on freeways in Chicago since the 1960s.
The I-540 lights are a test for the state, said DOT spokesman Steve Abbott. If they’re successful there, DOT would look to install them on other busy ramps in North Carolina.
The signals will be installed on the westbound on-ramps at Falls of Neuse, Six Forks, Creedmoor and Leesville roads and will be used during the morning rush hour and at other times of heavy traffic, such as after an accident, Abbott said. The lights will be turned off when not in use.
DOT chose the four ramps in part because of their length, Abbott said. The lights will be placed about halfway down the ramps, giving drivers enough space to get up to speed from a dead stop.
“You have to have a long enough ramp to get up to highway speed,” he said.
Sensors in the pavement will detect if traffic from the on-ramp is backing up onto the road and will turn the light green long enough to clear the backup. NCDOT’s traffic operations center will monitor the ramps via cameras and can manually adjust the signals if necessary.
The ramp meters will cost an estimated $2.1 million to install, and DOT hopes to have them in place by next spring. It will hold a public meeting to explain how they’ll work and answer questions on Thursday, Sept. 29, at the Abbotts Creek Community Center on Durant Road in Raleigh. The meeting will run from 4 to 7 p.m.
For more information
The N.C. Department of Transportation has a website to explain the ramp signals at www.ncdot.gov/projects/onrampsignals/