The Colorado Department of Transportation (CDOT) says that more than a dozen Variable Speed Limit (VSL) signs are now live on I-70 in Dowd Canyon.
On January 27, 2026, CDOT announced that 18 new VSL signs have been deployed on I-70 west of Vail, in Dowd Canyon, between mile markers 169 and 173. The VSL signs will replace the old static speed limit signs.
The VSL signs are equipped new technology automatically adjusts the speed limit displayed on the sign based on congestion, visibility, traffic conditions and adverse weather such as a snow storm and icy roads.
“Posting the appropriate speed limit in real-time helps prevent crashes and improves traffic flow through the corridor. The beacons flash only when the speed limit is lowered due to adverse road conditions. The beacons remain dark and do not flash when the speed limit is normal,” CDOT said.
The speed limit displayed on the VSL signs will be enforced by police, and drivers who exceed the limits posted on the electronic signage can be cited.
“This milestone represents CDOT’s investment into technologies to enhance driver safety and improve traffic flow along one of Colorado’s most heavily traveled mountain corridors,” said CDOT Executive Director Shoshana Lew. “Statewide, weather- and congestion-based VSL algorithms are among the cutting-edge tools CDOT uses to enhance motorist safety.”
VSL signs are also in use on the I-70 Mountain Express Lanes and in Glenwood Canyon.
CDOT hopes that increased VSL sign deployment will improve roadway safety.
“The Federal Highway Administration reports VSLs can reduce total crashes by 34%, injury/fatal crashes by 51%, and rear-end crashes by 65%. In Colorado, along the I-70 Mountain Corridor, preliminary data indicates a 20% drop in crashes in the eastbound Mountain Express Lanes since VSL implementation, particularly during busy periods,” the agency said.