Safety Metering

What is Safety Metering?

Of the 97-mile stretch on I-70 between Denver and Vail, no segment is more important than the 1.7 miles through the Eisenhower Tunnel—connecting Colorado's eastern and western slopes, and traversing the continental divide.

With more than 30,000 vehicles passing through the tunnel daily, keeping the tunnel clear and operating continuously presents a challenge, especially with the increased volume of weekend I-70 winter traffic.

Among CDOT's arsenal of tools to mitigate I-70 traffic is safety metering. While drivers may be stopped an average of 20 minutes with safety metering, the actual delay is only around 3.5 minutes. This is because eastbound traffic on the other side of the Eisenhower Tunnel is still moving slowly and cars usually quickly catch up with the flow of traffic.

Blue snowflake divider

This occurs on the approach to the Eisenhower Tunnel. An alternating red and green stoplight cycles every four to eight seconds to keep traffic moving consistently through the tunnel, while traffic on the tunnel's east side slowly dissipates.

This occurs at eastbound on-ramps at Copper Mountain, Frisco, Silverthorne, and Loveland. This type of metering may be more familiar, occurring on highway and interstate on-ramps throughout most metro areas.

Safety metering is triggered by high traffic, accidents or adverse weather, but with either type of metering, the goal is the same: prevent traffic back-ups in the Tunnel. The Tunnel needs to remain open for emergency vehicles to get through, which allows them to react to and clear the emergency more quickly.