Congestion along North Carolina's freeways is growing, especially during peak travel times, such as morning and evening commute times. While traffic volumes increase, 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.
NCDOT, however, can optimize traffic flow on freeways by using technologies such as on-ramp signals, which are a cost-effective and proven way to reduce travel times on the freeway and make them more reliable.
On-Ramp Signal Basics
Also known as ramp meters, on-ramp signals are generally used during peak travel times (e.g., morning and evening commutes) 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 a more reliable freeway travel times
- Smoother merges, which means improved safety and fewer crashes
How On-Ramp Signals Work
On-ramp signals are stop-and-go signals on freeway entrance ramps that 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, which creates a gap between vehicles and regulates – or meters – vehicles merging onto the freeway.
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.