Ramp meters are traffic signals placed where on-ramps enter freeways or other major thoroughfares.
The meters resemble traditional traffic lights, but have only a red and green light (no yellow). On-ramps with two or more lanes have separate ramp meter lights for each lane of travel. Often, ramp meter lights rotate every few seconds, with one lane displaying green and the other displaying red.
Cars driving on the on-ramp to enter the freeway stop at the red light. When the light turns green, one car can enter the freeway at a time.
Some metered ramps have bypass lanes which allow high-occupancy vehicles such as carpools and buses to skip the ramp meter and directly enter the freeway.
Using Ramp Meters
There are a few simple steps to using ramp meters:
1. Pull up to the line
Drive your vehicle up to the painted stop bar on the pavement next to the ramp signal (or stop behind any vehicles which may be stopped in front of you approaching the ramp meter). Make sure you can see the signal, and remain alert because the light may change from red to green more rapidly than a signal at an intersection.
2. Wait for the green light
When the signal turns green, one car per lane may leave the ramp and merge safely onto the freeway. If your light is red, wait until it turns green and proceed onto the freeway.
Warning – Traffic violations may result in fines. Failing to stop at a ramp meter when it is in operation is a traffic violation similar to running a red light.
Below are some of the benefits that can be provided by ramp meters:
- Reduce congestion on freeway
- Maintain more steady traffic flow and regular travel speeds on freeway
- Allow more cars to use the freeway
- Increase safety by helping to reduce crashes associated with stop and go traffic and high-speed merging
- Allow merging vehicles to enter freeway traffic more smoothly
When many vehicles merge onto an already-crowded freeway at once, drivers on the freeway are forced to slow down to let cars enter from the ramp, potentially causing sudden speed changes, backups and crashes.
Ramp meters create a safer, less congested freeway. By controlling the frequency and spacing of vehicles merging onto a freeway, ramp meters minimize freeway speed disruptions and improve traffic flow.
Research shows that most freeway accidents occur during stop-and-go traffic. Ramp signals provide a smoother traffic flow, which minimizes stop-and-go traffic. Freeway accidents can be reduced due to ramp meters.
The Nevada Department of Transportation and partners have installed ramp meters along certain major Nevada interstates and freeways, particularly in the Las Vegas area. In 2011, ramp meters began being installed on certain interstate on-ramps in the Reno area as well.