From Denver, U.S. 36 runs through Boulder, Lyons, and Estes Park to Rocky Mountain National Park. The direct route from Denver to Grand County is I-70 west to U.S. 40 (Empire Exit) and to U.S. 34. If you're driving directly to Fort Collins or Estes Park and Rocky Mountain National Park from Denver International Airport, the E-470 tollway connects Denver International Airport's Peña Boulevard to Interstate 25. U.S. 36 between Boulder and Estes Park is heavily traveled. Colorado Routes 119, 72, and 7 have much less traffic.
Gasoline and service are available in all larger towns and cities in the region. Bicyclists are common except on arteries; state law gives them the same rights and holds them to the same obligations as any other vehicle. Expect extensive road construction along the northern Front Range; arterial routes, state highways, and city streets are being rebuilt to accommodate increasing traffic in the urban corridor. Although CDOT plows roads efficiently, a winter snowstorm can slow traffic with wet, slushy, or icy conditions. A cell phone is recommended, since some mountain roads have long, uninhabited stretches.
AAA Colorado (303/753-8800). CDOT Road Information (303/639-1111 or 877/315-7623. www.dot.state.co.us). Colorado State Patrol (303/239-4501; *277 from cellular phone). Rocky Mountain National Park Road Information (970/586-1333).