New electronic variable-speed limit signs went live in mid-January along a high-risk stretch of Interstate 70 in Dowd Canyon west of Vail, automatically adjusting posted speeds to match real-time traffic congestion, weather and road conditions.

It’s an effort by the Colorado Department of Transportation to try and reduce crashes on one of Colorado’s busiest mountain corridors, according to a news release.

CDOT activated 18 LED signs on Jan. 12, after months of testing to verify system reliability in the canyon. The signs cover the corridor, from east to west, between these exits:

– Exit 169: Eagle-Vail / U.S. Highway 6 

– Exit 171: Dowds Junction / U.S. Highway 24 / Minturn and Leadville

– Exit 173: West Vail 

Flashing beacons on some signs alert drivers when limits are reduced due to adverse conditions such as snow, ice, or low visibility.

“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,” Shoshana Lew, CDOT executive director, said in the release. “Statewide, weather- and congestion-based VSL algorithms are among the cutting-edge tools CDOT uses to enhance motorist safety.”

The Federal Highway Administration reports that variable speed limit systems can reduce total crashes by 34%, injury and fatal crashes by 51%, and rear-end crashes by 65%. Preliminary data along the I-70 mountain corridor show a 20% drop in crashes in the eastbound Mountain Express Lanes since similar variable-speed technology was implemented, particularly during peak periods, said the release.

Dowd Canyon is a heavily traveled mountain roadway without frontage roads in that stretch to allow for diverting traffic around incidents, according to CDOT, making closures particularly disruptive and costly. The department said it selected this segment for variable speed limits as an additional measure to prevent crashes and maintain smoother flow through the critical corridor.

Similar systems operate elsewhere on I-70, including the Mountain Express Lanes and Glenwood Canyon.

The posted speed on the signs is not a suggestion, according to CDOT. Drivers exceeding the displayed limit face speeding citations.

Motorists are encouraged to check conditions in advance. Resources include the COtrip.org website, the COtrip Planner mobile app, available for iOS and Android, project and travel alerts at bit.ly/COnewsalerts, scheduled construction lane closures at bit.ly/laneclosures, and CDOT’s social media channels on Twitter, Facebook, Instagram and YouTube.