As Colorado moves into the peak of winter, state agencies are implementing new measures to improve safety and reliability along the Interstate 70 Mountain Corridor. The Colorado Department of Transportation (CDOT), State Senator Dylan Roberts, and the Colorado State Patrol have announced a key change: commercial motor vehicles (CMVs) are now restricted from using the left lane on several high-risk segments of I-70 unless they are actively passing.
New signage and lane markings have been installed at locations including Georgetown Hill, Eisenhower Johnson Memorial Tunnels, Vail Pass, and Glenwood Canyon. The restriction is intended to keep heavy trucks in the right lane to help maintain steady traffic flow and reduce crash risks on steep grades that can be affected by winter weather.
CDOT has also increased its winter operations capabilities this season. Maintenance staffing is nearly full across the state, with upgraded snowplow fleets, improved de-icing technology, and specific surge deployments for the I-70 corridor. Crews work continuously during storms to clear roads, maintain traction, and respond quickly to emergencies.
According to CDOT Executive Director Shoshana Lew, “Every minute matters during a winter storm. When a semi blocks the left lane on Vail Pass or the Eisenhower Johnson Memorial Tunnels approach, it can shut down travel for hours. This restriction helps prevent those closures and gives our crews the room they need to keep the corridor open.”
State Senator Dylan Roberts commented on the collaborative legislative effort behind these rules: “My constituents along the I-70 corridor and I are thrilled to see these left lane restrictions and prominent warnings go into effect. We worked hard, in a bipartisan manner, to pass SB24-100 which put in place these left lane rules, among other measures, which will cut down on unnecessary crashes, spin-outs, and delays for I-70 travelers. This is good, common-sense action by CDOT that will keep people safe and keep our roads open.”
The Colorado State Patrol is enforcing these restrictions at Floyd Hill, Georgetown Hill, Eisenhower Johnson Memorial Tunnels, Vail Pass, Dowd Junction, and Glenwood Canyon through regular patrols. Troopers will identify trucks violating the rule—especially during storms or peak periods—and violators may face fines or points against their licenses.
Lt. Colonel Joshua Downing of the Colorado State Patrol stated: “This law, coupled with the expanded chain law, is intended to reduce or prevent traffic delays, closures and devastating crashes. Professional drivers hold responsibility, just like every other driver, to be prepared and courteous when traveling in winter conditions. Together, we can keep I-70 moving safely.”
The CMV left-lane restriction supports CDOT’s de-icing strategy by keeping traffic flow predictable so anti-icing materials work effectively. By limiting trucks to lanes receiving frequent plowing and treatment during severe weather events—which is marked by road crews—officials aim to lower incidents such as jackknifes or complete shutdowns on challenging sections of I-70.
Crews have added road markings indicating where commercial motor vehicles are not permitted in the left lane.
