Speed, Mountains & Road Conditions
Speed must always match conditions, and Colorado's mountain roads and winter weather demand extra care.
Basic speed law
You must never drive faster than is safe for current conditions, even when you are below the posted limit. Rain, snow, ice, fog, heavy traffic, and darkness all require you to reduce your speed to keep control of your vehicle.
Mountain and downhill driving
On long, steep downgrades, shift to a lower gear so the engine helps control your speed and your brakes do not overheat and fail. Slower traffic and heavy trucks should use the right lane and pull into turnouts to let faster traffic pass.
Winter and chain rules
Colorado's traction and chain laws can require passenger vehicles to have snow tires, all-weather tires, or chains on mountain corridors during winter storms. A slow-moving vehicle traveling under 25 mph displays an orange-and-red reflective triangle; slow down and pass only when it is safe.