The Colorado Department of Transportation opened one lane of Interstate 70 through Glenwood Canyon in each direction at 3:05 p.m. yesterday, almost four days after a cascade of boulders pounded the road, blocking passage.

The slide early Monday punched holes in a bridge, destroyed guardrails and left boulders the size of semi tractors scattered over the roadway.

It forced truckers and other travelers onto a 200-mile detour that added hours to their trips and ratcheted up costs, including for fuel.