Project overview
To keep travelers and freight moving smoothly across Washington, contractor crews installed ramp meters on six Interstate 5 on-ramps. This system helps reduce traffic, improve safety, and keep trips reliable along the I-5 corridor in Lewis County between Chehalis and Centralia.
What to expect
Ramp meter locations
- Northbound I-5 at 13th Street/Parkland Drive (Exit 76)
- Northbound I-5 at State Route 6/Main Street (Exit 77)
- Northbound I-5 at Chamber Way (Exit 79)
- Southbound I-5 at Harrison Avenue (Exit 82)
- Southbound I-5 at Mellen Street (Exit 81)
- Southbound I-5 at SR 6/Main Street (Exit 77)
How ramp meters work
Ramp meters are traffic signals at highway on-ramps. When traffic is heavy, the meter turns on and allows one vehicle at a time to enter the highway. This creates safe gaps between vehicles, making it easier to merge and helping keep freeway speeds steady. Studies show ramp meters can reduce collisions by 30 percent.
How to use ramp meters
Drive up to the white stop line on the ramp. If the light is red, stop. When it turns green, accelerate and merge onto the highway. These ramp meters let only one vehicle through per green light, with a short delay between each. WSDOT’s goal is to balance the needs of drivers merging onto the highway with the needs of drivers already there.
On-ramp delays
Ramp meters help traffic flow for drivers already on the highway, but can cause brief delays for those merging on. Unlike other states, Washington’s meters don’t follow a set schedule. They adjust in real-time based on traffic and crews monitor each ramp closely and fine-tune after activation. WSDOT’s goal is to balance the needs of drivers merging onto the highway with the needs of drivers already there.
This image shows the stretch of I-5 that has been improved with newly installed ramp meters.
Needs & benefits
During weekday peak commute times, typically 4 to 6 p.m. and 12 to 2 p.m. on Fridays, congestion on I-5 near Chehalis increased. Contractor crews improved traffic flow between Chamber Way and the SR 6 and Mellen Street interchanges by installing ramp meters. Now that the project is complete, travelers can expect less congestion, shorter travel times, and safer, more reliable trips.
Safety
- Between 13th Street (Parkland Drive) and Harrison Avenue, collisions have increased by nearly 40 percent during peak commute times between 2014 and 2018.
- There were a total of 1,146 crashes in the study area. Two-thirds of the collisions in the study area were rear-end and side-impact crashes, which are generally associated with congested traffic conditions.