Passenger Vehicle Traction & Chain Laws
If weather conditions require, CDOT can implement Passenger Vehicle Traction and Chain laws. Motorists will be alerted to an active Traction Law or Chain Law by highway signage, COtrip.org or traffic/roadway condition alerts. (Sign up for alerts via text or email.).
Traction Law (Code 15)
During an active Traction Law (also known as a Code 15), motorists must have either snow tires, tires with the mud/snow (M+S) designation, or a four-wheel/all-wheel drive vehicle. All tires must have a minimum one-eighth inch tread. You can also install chains or an alternative traction device (like AutoSock) to be in compliance with the law if your tires aren't adequate.
- Find out if your tires meet the minimum one-eighth inch tread requirement by taking the Quarter Test.
Passenger Vehicle Chain Law (Code 16)
During severe winter storms, CDOT will implement a Passenger Vehicle Chain Law (also known as a Code 16). This is the final safety measure before the highway is closed.
When the Passenger Vehicle Chain Law is in effect, every vehicle on the roadway must have chains or an alternative traction device (like AutoSock).
- Motorists driving with inadequate equipment when a Passenger Vehicle Traction Law or Chain Law is in effect could be fined more than $130.
- If a motorist blocks the roadway because he/she has inadequate equipment when a Passenger Vehicle Traction Law or Chain Law is in effect, he/she could be fined more than $650.
- Download a Passenger Vehicle Traction Law and Chain Law fact sheet.
- See a printed version of the FAQ below.
Frequently Asked Questions
If you're not driving a four-wheel or all-wheel drive vehicle, all-weather/all- season tires do not meet the tire requirement under the Traction Law unless they have a mud and snow rating — this designation is normally written on the sidewall of the tire as "M+S" or "M&S." If you are driving a four-wheel or all-wheel drive vehicle, all-weather/all-season tires meet the requirement if all four tires have a minimum one-eighth inch tread.
All-wheel drive and four-wheel drive are not the same, but under the Traction Law, both are compliant as long as all the tires have a minimum one-eighth inch tread. While all-wheel drive and four-wheel drive are great for getting going in slick or snowy conditions, when it comes to stopping, nothing is more important than your tires. In winter conditions, snow tires stop much more quickly than all-season tires. For more information about tire stopping distance, head to winter.codot.gov/tires.
To learn about the difference between all-wheel and four-wheel drive, keep reading.
There are two main kinds of four-wheel drive — part-time and full-time. With part-time four-wheel drive, most vehicles are rear-wheel drive until the driver manually puts the vehicle in four-wheel drive. With full-time four- wheel drive, all four wheels are always engaged.
With all-wheel drive, sensors automatically determine which wheels should get power to maximize traction. During normal conditions, most all-wheel drive vehicles use just the front wheels.
All that said, a front-wheel drive vehicle with snow tires will perform better than an all-wheel or four-wheel drive with all-season tires in nearly any turning or stopping situation. The key takeaway is that tires mean everything when it comes to stopping. Click here to see a video showcasing this fact.
Under a Traction Law, both metal-studded and studless snow tires comply with the "snow tire" requirement of the law. CDOT recommends using studless snow tires instead of studded because studded tires can chip and cut grooves in the road, creating a hydroplaning hazard when the roadway is wet. Whether using studded or studless snow tires, all the tires must have a minimum one-eighth inch tread.
Most all-terrain tires meet the tire requirement, but double-check yours to make sure. You'll want to look for a mud and snow rating ("M+S" or "M&S") or snowflake icon on the sidewall of the tires.
You always want to put chains or alternative traction devices (like an AutoSock) on the "drive" wheels of the vehicle. You would install them on the front wheels of a front-wheel drive vehicle or on the rear wheels of a rear-wheel drive vehicle. On a four-wheel drive or all-wheel drive vehicle, the chains or alternative traction devices are generally used on just the rear wheels, but to retain as much of the normal handling characteristics as possible, chains should be installed on all four tires.
An adequate tire under the Traction Law needs to have a minimum one- eighth inch tread on all four tires. If you're not in a four-wheel or all-wheel drive vehicle, those tires need to be snow tires or have a mud & snow (M+S) rating. To find out if your tires meet the tread depth minimum, take the Quarter Test.
During an active Traction Law, you can put on chains or an alternative traction device (like an AutoSock) and be in compliance with the law. Be sure to only pull over at designated chain up areas to stay safe.
No. An alternative traction device is something like the AutoSock. Under an active Passenger Vehicle Chain Law, every passenger vehicle will need to have chains or an alternative traction device equipped.
Most "snow" tires will be designated with a snowflake symbol AND an M+S mark on the tire. Some all-season/all-weather tires have a mud and snow rating, and that is designated with the M+S mark. Any tires with a snowflake or M+S mark comply with the Traction Law, as long as all the tires have a minimum one-eighth inch tread.
To be an approved tire under the Traction Law, they will need to have a snowflake mark (designating a snow tire) or a mud and snow (M+S) mark — all tires must have a minimum one-eighth inch tread. If you drive a four- wheel drive or all-wheel drive vehicle, all of your tires just need to have a minimum one-eighth inch tread.
Yes to both questions. During a Passenger Vehicle Chain Law, every passenger vehicle must be equipped with chains or an alternative traction device (like an AutoSock). If you are driving without the proper equipment, you could be fined more than $130. If you block the roadway because you don't have the proper equipment, you could be fined more than $650. If you aren't carrying chains or a traction device with you, you will be required to wait until the chain law is lifted.
Both laws apply to the entire state, but during the 2015/16 winter, you'll likely only see if called along the I-70 Mountain Corridor and connecting highways. During the 2016/17 winter, you will see the law activated along all interstates and state highways.
There is no "limp home" provision under either law. If you do not have the proper equipment during either law, you can be fined and restricted from the roadway for not only your safety, but also the safety of those around you. The best thing to do is make sure you have safe tires for winter driving and carry chains or an alternative traction device (like an AutoSock) in your vehicle at all times.