CO SB173

Prohibits vehicles with gross vehicle weight rating over 26,000 pounds from driving in the far left lane of Interstate 70 on grades of 6% or more for at least one mile

Allows exceptions for vehicles to use left lane when obeying traffic control devices, entering or exiting I-70, during weather conditions requiring slower speeds, or during heavy traffic that reduces speeds to at least 20 mph below the speed limit

Requires the Department of Transportation to post signs notifying drivers of this restriction

Prohibits the Department of Transportation from setting speed limits for commercial vehicles or any motor vehicle class that differ by more than 25 mph from the highest authorized speed for other vehicle classes on the same highway portion

Takes effect July 1, 2010, and applies to offenses committed on or after that date