Colorado Department of Transportation CoTRiP Real-Time Road & Weather



  Chain Regulations
Passenger Vehicles
Winter Tire Tread Requirements

The Colorado Chain Law is the popular term for the requirement for use of tire chains or adequate snow tires on mountain highways during heavy snow conditions. The term is somewhat misleading because chains are not always required. There are two levels of the law that may be invoked as follows:

 
  Chains or Snow Tires Required
This level requires the use of adequate snow tires or traction devices such as cable chains, etc. Snow tires must have the mud and snow (M/S) or all weather rating from the manufacturer on the side wall.
  Chains Only
When this level is in effect, use of conventional, steel-link chains is required. Four-wheel drive vehicles are permitted to operate without tire chains when four wheel drive is engaged.

• Studded tires can be used the year around in Colorado

  When Snow Tires Are Required:
• Conventional mud and snow tread with (M/S) with or without studs and a minimum tread depth of 1/8".

• Tires of the all weather type bearing the mark M/S with a minimum tread depth of 1/8".

• Four-wheel drive vehicles (all four wheels engaged) with adequate tires. Adequate tires for four-wheel drive vehicles include those with conventional tread with a minimum tread depth of 1/8" and those listed in 1) or 2) above.

• Wavy snow-treads with steel wire protruding.

• Any conventional tire with a minimum tread depth of 2/32" when used in conjunction with chains as mentioned in "Chain Only" section.