Ramp meters go live on I-5 between Chehalis and Centralia

New signals will activate one by one to cut congestion and save time

LEWIS COUNTY - Travelers in Lewis County will soon see new ramp meters turn on to help traffic on Interstate 5 move smoothly and safely.

Starting Monday, Aug. 18, the Washington State Department of Transportation will begin activating six traffic signals on I-5 on-ramps between Harrison Avenue in Centralia and 13th Street/Parkland Drive in Chehalis.

This project also added new pavement striping on those six I-5 on-ramps to make merging safer, reduce crashes and keep traffic moving during busy times.

After the ramp meters and electrical systems were installed, they stayed off while collecting traffic data. This "dormant" period helps gather information needed to run the signals effectively. When enough data is collected, the ramp meters are ready to turn on. They then use that data and real-time traffic to decide when vehicles can safely merge onto the highway.

What drivers can expect

• Ramp meters will turn on one at a time, starting at 13th Street/Parkland Drive and moving north as each signal is adjusted and fine-tuned.
• Traffic engineers will watch each meter after it's activated to make sure it works correctly.
• The signals will only be in use during heavy traffic based on real-time conditions, not a set schedule.

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.

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)