CDOT launches variable speed limit sign technology on eastbound I-70 between Georgetown and Idaho Springs

Clear Creek County - Variable speed limit (VSL) signs on a 10-mile stretch of eastbound I-70 between Georgetown and Idaho Springs will go live on Tuesday, March 12, 2024. A variable speed limit sign is an electronic version of a regular speed limit sign with an LED display of the regulatory speed limit number (i.e. the enforceable speed limit) which can be changed to best suit conditions on the highway.

The Colorado Department of Transportation replaced the 13 aging VSL signs and installed 13 new ones so there are signs on both sides of the highway, making it easier for drivers in any lane to see the speed limit. The project added new vehicle speed/volume and weather detectors to gather real-time and consistent traffic and weather data. This new technology automatically adjusts the speed limit based on congestion, traffic conditions and adverse weather such as a snow storm and icy roads. Posting the appropriate speed limit in real-time will help prevent crashes at higher speeds, reduce the chances of secondary crashes and improve traffic flow through the corridor.

“The key purpose behind the new signs is to improve safety on the I-70 mountain corridor, said Jessica Myklebust,” the director of CDOT’s Region 1, covering the Denver metro region. “VSLs react to real-time congestion and incidents on the corridor, reducing speeds to a reasonable limit when needed. This helps to prevent crashes and “stop and go” traffic. VSLs have been shown to improve safety and operations on highways nationwide.”

It’s important to note the speed limit will not change all the time, ONLY when there are bad weather conditions or congestion that warrant a change. One example is if there is a crash ahead on the highway, the variable speed limit signs can be changed to slow traffic down before reaching the back of the traffic queue to reduce the chances of a secondary crash. Similarly, if there is a snow storm on the corridor that may cause slick conditions, the speed limit will be lowered to slow drivers down.

The speed limit posted on VSLs is the enforceable speed limit and is not a recommended or suggested speed limit. This means that a driver traveling at speeds greater than what is posted can be ticketed for speeding.

The VSL signs were installed on this section of eastbound I-70 in 2022. There are VSLs being used in Glenwood Canyon and there are also upcoming efforts to use variable speed limits in other areas in the state, such as Wolf Creek Pass.

For more information go to the I-70 Eastbound Variable Speed Limit Signs between Empire and Idaho Springs project webpage.