Congestion along North Carolina's freeways is growing, especially during peak travel times such as morning and evening commutes. While traffic volume is increasing, the amount of available funding and physical space limit the N.C. Department of Transportation's ability to widen existing highways and build new ones.
But NCDOT can optimize traffic flow by using technologies such as on-ramp signals, which are a cost-effective and proven way to reduce travel times on freeways and make them more reliable.
On-Ramp Signal Basics
Also known as ramp meters, on-ramp signals are generally used during peak travel times but can be activated any time in response to special circumstances affecting traffic flow, such as special events, wrecks or construction.
Benefits of on-ramp signals include:
- Smoother traffic flow, which means more reliable freeway travel times
- Smoother merges, which means improved safety and fewer crashes
How On-Ramp Signals Work
On-ramp signals regulate or meter traffic merging onto a freeway. They work just like traffic signals commonly used on roadways. When they are activated, vehicles on the ramp must stop when the signal is red and wait until it turns green before proceeding to the freeway. Only one or two vehicles are allowed to merge at a time, creating a gap between vehicles.
On-Ramp Signal Locations
The first on-ramp signals in North Carolina became operational in September 2017 along westbound I-540 at four ramps in north Raleigh:
- Falls of Neuse Road (Exit 14)
- Six Forks Road (Exit 11)
- Creedmoor Road (Exit 9)
- Leesville Road (Exit 7)
These sites were selected as pilot sites based on in-depth studies completed in 2013. NCDOT is also evaluating on-ramp signals for Charlotte-area interstates.