CO:
During winter storms, or when conditions require, CDOT will implement the Passenger Vehicle Traction Law. CDOT can implement the Passenger Vehicle Traction and Chain Laws on any state highway. During a Traction Law, all motorists are required to have EITHER:
- 4WD or AWD vehicle and 3/16” tread depth
- Tires with a mud and snow designation (M+S icon) and 3/16” tread depth
- Winter tires (mountain-snowflake icon) and 3/16” tread depth
- Tires with an all-weather rating by the manufacturer and 3/16” tread depth
- Chains or an approved alternative traction device
CA:
During the winter months, motorists may encounter traction chain controls in the mountain areas within California. When chain controls are established, signs will be posted along the road indicating the type of requirement. There are
Three Levels of Chain Requirements in California:
- Requirement 1 (R-1): Chains are required on all vehicles except passenger vehicles and light-duty trucks under 6,000 pounds gross weight and equipped with snow tires on at least two drive wheels. Chains must be carried by vehicles using snow tires. All vehicles towing trailers must have chains on one drive axle. Trailers with brakes must have chains on at least one axle.
- Requirement 2 (R2): Chains or traction devices are required on all vehicles except four-wheel/all-wheel drive vehicles with snow-tread tires on all four wheels.
NOTE: (Four-wheel/all-wheel drive vehicles must carry traction devices in chain control areas.)
- Requirement 3 (R3): Chains or traction devices are required on all vehicles, no exceptions.
R-1 and R-2 are the most common conditions. A highway will often be closed before an R-3 condition is imposed. Some local areas may use variations of these designations. You must follow the directions on the signs posted for chain controls or any instructions given by Caltrans or CHP personnel at chain control check points, even if these are at variance with broadcast road condition reports or information contained herein.
1 Snow-tread Tires: The California Vehicle Code, Section 558 defines a snow-tread tire as follows, "A 'Snow-tread tire' is a tire which has a relatively deep and aggressive tread pattern compared with conventional passenger tread pattern". Snow-tread tires can be identified by examining the sidewall of the tire where the letters MS, M/S, M+S or the words MUD AND SNOW have been stamped into the sidewall.
On a side note, I saw 3 cars blocking all 3 lanes up Vail pass this weekend. All were front wheel drive (cars and SUV) and non could get started up the hill. Kinda sad for a 2-lane highway on I-70. AWD vehicles had no issues getting around them.
With that said, I run Blizzak's on the Highlander/4runner and Sottozero's on the Tesla.