The couple was in their 50s, said Jann Smith, coroner for La Plata County. Their names were not immediately released because authorities needed to contact family members.
The husband was declared dead at the scene on U.S. Highway 160. The Colorado State Patrol first got a call about the accident around 2:15 p.m., said Trooper Josh Lewis.
No other vehicle was involved in the accident.
The accident caused the highway to close to both directions of traffic for a couple of hours. The highway was reopened about 4:20 p.m.