Travel Center

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 or Chain Law by highway signage, COtrip.org or GovDelivery notifications — to sign up for GovDelivery emails and/or text notifications, click here .

Traction Law (Code 15)
During an active Traction Law, also known as a Code 15, motorists will need to 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. During a Passenger Vehicle Chain Law, every vehicle on the roadway is required to have chains or an alternative traction device (like AutoSock).

Fines
Motorists driving with inadequate equipment during a Passenger Vehicle Traction or Chain Law could be fined more than $130.

If a motorist blocks the roadway because they have inadequate equipment during a Passenger Vehicle Traction or Chain Law, they could be fined more than $650.

To download a Passenger Vehicle Traction and Chain Law fact sheet, click here.

Click here to view a printable version of the Frequently Asked Questions (FAQs) regarding the Passenger Vehicle Traction and Chain Law.

Frequently Asked Questions

Do all-weather tires meet the tire requirement under the Traction Law (Code 15)?

Is all-wheel drive and four-wheel drive the same thing?

The Traction Law (Code 15) specifies that snow tires are required. Does this include metal-studded and studless snow tires?

Do all-terrain tires meet the tire requirement under the Traction Law (Code 15)?

Which wheels need chains?

What is an “adequate” all-weather or all-season tire?

If I have a passenger vehicle and CDOT declares the Traction Law, would chains clear me for driving even though they are not required until a Passenger Vehicle Chain Law (Code 16)?

If the Passenger Vehicle Chain Law (Code 16) were to go into effect, would all- wheel drive or four-wheel drive be considered an alternative traction device and not need chains?

Do my tires have to have the M+S designation on them in order to qualify as proper snow tires?

There are various tire designations: AT (All terrain), AS (All Season), AT-AS (Both) Some have no markings at all but are sold as snow tires. Do they fit the requirements?

What if I meet the requirements for the Traction Law (Code 15), but mid-trip a Passenger Vehicle Chain Law (Code 16) is activated. If I have no chains, will I be ticketed? Will I be asked to wait until the chain law is lifted?

Do the Traction Law (Code 15) and Passenger Vehicle Chain Law (Code 16) apply to only I-70 or to the entire state?

Is there a “limp home” provision during either the Traction Law (Code 15) or Passenger Vehicle Chain Law (Code 16)? Example: if a law goes into effect while at work, can we drive home?

Swipe table to see more content

Do all-weather tires meet the tire requirement under the Traction Law (Code 15)?

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.

Is all-wheel drive and four-wheel drive the same thing?

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.


The Traction Law (Code 15) specifies that snow tires are required. Does this include metal-studded and studless snow tires?

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.

Do all-terrain tires meet the tire requirement under the Traction Law (Code 15)?

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.

Which wheels need chains?

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.

 

What is an “adequate” all-weather or all-season tire?

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.

If I have a passenger vehicle and CDOT declares the Traction Law, would chains clear me for driving even though they are not required until a Passenger Vehicle Chain Law (Code 16)?

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.

 

If the Passenger Vehicle Chain Law (Code 16) were to go into effect, would all- wheel drive or four-wheel drive be considered an alternative traction device and not need chains?

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.

 

Do my tires have to have the M+S designation on them in order to qualify as proper snow tires?

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.

 

There are various tire designations: AT (All terrain), AS (All Season), AT-AS (Both) Some have no markings at all but are sold as snow tires. Do they fit the requirements?

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.

 

What if I meet the requirements for the Traction Law (Code 15), but mid-trip a Passenger Vehicle Chain Law (Code 16) is activated. If I have no chains, will I be ticketed? Will I be asked to wait until the chain law is lifted?

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.

 

Do the Traction Law (Code 15) and Passenger Vehicle Chain Law (Code 16) apply to only I-70 or to the entire state?

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.

 

Is there a “limp home” provision during either the Traction Law (Code 15) or Passenger Vehicle Chain Law (Code 16)? Example: if a law goes into effect while at work, can we drive home?

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.

Filed under:
Colorado: The Official State Web Portal