Ramp meters are traffic lights that control the frequency in which vehicles enter the flow of traffic on to the interstate during peak travel times. They are a proven cost-effective tool to reduce congestion while improving traffic flow and safety by providing spaced intervals between vehicles, rather than having multiple vehicles enter the freeway at once, clogging up the system. More efficient merging allows mainline traffic to continue travelling smoothly and keeps traffic flowing at highway speeds.
FAQ'S
How do I use ramp meters?
Drive your vehicle up to the white line, or stop bar/fog line, to trigger the ramp meter. If the light is red, stop at the white line. When the light turns green, continue to merge onto the freeway.
How do ramp meters work?
Ramp meters are part of a large computer-operated system that is managed in WSDOT's Traffic Management Center (TMC). Electronic monitoring systems provide the TMCs with information about traffic flow, such as the volume and speed of vehicles on highways and ramps. Data is fed to the ramp meters. The meters automatically alter cycles to maximize traffic flow on both the ramps and the freeways.
Why are they effective?
Without ramp meters, multiple cars merge simultaneously. Drivers on the highway slow down to allow the cars to enter and these slower speeds quickly cause backups. If cars enter the highway in controlled intervals, they are less likely to cause a disruption to highway traffic.
A short wait on the ramp allows drivers to increase their average highway speed and shorten overall highway travel times. Ramp meters also decrease the potential for collisions, by up to 30 percent, that often occur when multiple vehicles merge onto the highway at the same time.
Why does WSDOT install ramp meters?
WSDOT uses ramp meters to help reduce the potential collisions and decrease travel times. Most ramp meters allow only one vehicle through each green light, creating a 4 to 15 second delay between cars entering the highway. This delay helps reduce disruptions to highway traffic and reduces collisions that occur when vehicles merge onto the highway.
Will the ramp meters cause backups on local streets?
There is always an adjustment period after new ramp meters are activated. This is the timeframe when the public becomes accustomed to using them. WSDOT will monitor traffic flows and make any adjustments to the meters if necessary.
This project is made up of both State & Federal Funding and is estimated to cost approximately $3.7 million
No additional maps and drawings
