Colorado plans to add another tolled express lane on Interstate 70 near Idaho Springs.
The Denver Post reports the $70 million project west of Denver will include a 12-mile (19-kilometer) zone where construction is expected to begin Monday.
Officials say the new westbound express lane will mirror an eastbound lane that opened in 2015.
The lane is expected to open in early 2021 and will extend from the Veterans Memorial Tunnels to the U.S. 40 exit at Empire Junction.
Officials say the construction will widen portions of the highway to accommodate the narrow lane, which will revert to a shoulder during off-peak hours.
The Colorado Department of Transportation will set varying toll rates for the lane.
Democratic Gov. Jared Polis says the toll lanes are "temporary solutions" for Highway 70.