One man is dead and another is seriously injured after a traffic accident in a construction zone on Colorado 470 in Douglas County.

The Colorado State Patrol says 40-year-old Christopher Chialtas of Highlands Ranch was driving in the right lane of eastbound C-470 early Saturday. The patrol says the right lane was closed for construction and the car driven by Chialtas struck the rear of a street sweeper and then hit other equipment.

Authorities say Chialtas, who wasn't wearing a seat belt, was pronounced dead at the hospital.

Construction worker Donald Pacheco of Pueblo was thrown from the street sweeper. The State Patrol says he had serious injuries and was taken to Littleton Hospital.

Authorities suspect alcohol was involved.