Snow Tires & Chains in the Cottonwood Canyons

No one wants to be halted for hours on their way to or from a day of enjoying the Central Wasatch Mountains. Unfortunately, though, a lack of understanding of Utah’s snow tire requirements can add to the traffic delays and dangers within the Cottonwood Canyons. 

Many people who enter the Cottonwood Canyons area during the winter season are unaware of UDOT’s tire traction requirements. During the August CWC Board meeting Kaitlin Marousis, UDOT’s GIS Manager of Operations & Maintenance, walked the Commission and public through the Utah Code requirements for traction devices and chains, otherwise known as R920-6 Rule.

Graphic from Utah Department of Transportation.

What is  R920-6 Rule?

Whenever the conditions of a road are determined dangerous by either UDOT, Utah Highway Patrol, or designated local law enforcement agencies, all vehicles can be restricted from entering the roadway unless they meet the snow tire or chain requirements outlined in this rule. The law states that all travelers will be notified when traction devices are required through the use of signage and UDOT traveler information systems. The rule is only valid between October 1st and April 30th. 


What does your car need to make it up the canyons without being ticketed or turned around? 

Mountain/Snowflake symbol or the M + S rated tires. This indicates that your tires can either stand severe weather or mud and snow conditions. These tires need to be on at least two of the primary drive wheels on the vehicle. Your tires need to have sufficient tread as well, or else a law enforcement officer could tell you to turn your car around. Chains are also considered viable traction controls. RV’s and buses are required to have chains on at least two of their wheels, while commercial vehicles with more than four tires are required to have chains on every wheel. While you may follow all of the requirements noted above, law enforcement they still refuse passage if they feel that your vehicle in unsafe.


During the August CWC Board meeting, Detective Ralph Arnold and Sargent Ed Twohill, of the Unified Police Department, shared some of their observations, concerns, and enforcement stories. They noted that drivers occasionally recognize that they need chains when they are already in the canyons, resulting in drivers putting chains on the roadway. Due to a lack of road shoulder because of snowy conditions, they can completely halt traffic— restricting emergency vehicles and all other traffic from moving forward. 

They also noted that many rental cars don’t come with sufficient tires or chains. Renters are often unaware that rental car tires are not up to standard and can be dangerous. The Central Wasatch Commission has recognized this issue and is engaging rental car companies on this issue.


What are possible solutions to increasing safety and compliance with R9620 Rule? 

  • Increased outreach and education about Rule R9620 at rental facilities and amongst canyon visitors. 
  • Increase ticketing of vehicles without chains or proper tires in ski-resort parking lots. However, this brings up the added complication of possible overnight storage of cars that can’t safely travel down the canyons. 
  • Investigate the possibility of investing in a form of RFID, or Radio Frequency Identification, tags that indicate adequate tires through a detection device when allowing people to enter the canyons. This could reduce wait times when ensuring compliance in the canyons, and mitigate the passage of unsafe vehicles through the area.

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