Colorado Traction Law Guide
Colorado's Traction Law,
Explained for Travelers
What the Traction Law and Chain Law actually require, why most rental cars do not comply, and how the rules shape airport and mountain transfers.
Colorado's Traction Law requires your vehicle to have four-wheel or all-wheel drive, or winter or mud-and-snow rated tires, with at least 3/16-inch tread depth. It is enforced on I-70 between Dotsero and Morrison from September 1 through May 31 and can be activated statewide during storms. Violations start around $130 and rise sharply if your vehicle blocks the road.
What does Colorado's Traction Law actually require?
The three ways to comply
Under the Traction Law (CDOT calls it Code 15) your vehicle must have one of the following: four-wheel or all-wheel drive with at least 3/16-inch tread on all tires; tires rated for winter use, marked with the mountain-snowflake symbol; or mud-and-snow rated tires marked M+S, again with at least 3/16-inch tread. Alternatively, any vehicle may comply by carrying and using chains or an approved alternative traction device.
The tread depth is the part people fail
Three-sixteenths of an inch is the number to remember, and it is more than the legal minimum for ordinary driving. A set of all-season tires with plenty of life left for summer commuting can still put you in violation on Vail Pass.
The Chain Law is a step above
When conditions worsen, CDOT can activate the Passenger Vehicle Chain Law (Code 16). At that point every vehicle — including all-wheel drive — must have chains or an approved traction device fitted. This is the strictest level short of a closure.
When and where does it apply?
The I-70 mountain corridor, all season
The Traction Law is in effect on I-70 between Dotsero (roughly mile marker 133) and Morrison (roughly mile marker 259) from September 1 through May 31 every year, regardless of whether it is snowing that day. That covers the entire Denver-to-ski-country stretch: Floyd Hill, Georgetown, the Eisenhower–Johnson Tunnel and Vail Pass.
Anywhere else, during a storm
Outside that corridor and window, CDOT can activate the Traction Law or Chain Law on any state highway when conditions call for it — including US 285 to Fairplay, US 40 over Berthoud Pass to Winter Park, US 6 over Loveland Pass, and I-25 during a Front Range storm.
How to check before you go
CDOT posts active traction and chain restrictions by segment on COtrip.org and on the overhead variable message signs along I-70. Restrictions can change within an hour, in either direction.
The rule change most drivers missed
Two-wheel drive has no tire-only option
Under Senate Bill 25-069, a two-wheel-drive vehicle must carry chains or an approved alternate traction device from September 1 through May 31, whatever tires it has. Winter tires do not substitute. When the Traction Law is active, the chains or device have to be installed on at least two drive tires, not sitting in the trunk. The Colorado State Patrol publishes the current requirements.
Rental counters now have to tell you
The same bill requires rental car companies to notify renters of the chain law and the penalties for breaking it. Read the paperwork they hand you. The disclosure does not come with chains, and it does not make the car compliant.
What are the penalties?
Two tiers
A traction law violation starts at roughly $130 with surcharges. If your non-compliant vehicle blocks the highway — spins out, cannot climb a grade, or requires a tow that stops traffic — the fine rises to roughly $650 with surcharges. Exact amounts are set by statute and change; CDOT publishes the current figures.
The real cost is the day
The fine is rarely the expensive part. A spun-out vehicle on the tunnel approach means a missed flight, a missed first chair, a tow bill at mountain rates, and hundreds of drivers behind you sitting in the queue you created.
Why are rental cars so often non-compliant?
The default rental is a two-wheel-drive car on all-season tires
Rental fleets at DEN are stocked for year-round national demand, not for Vail Pass in February. An economy or midsize sedan with two-wheel drive and worn all-season tires satisfies no branch of the Traction Law, and the rental counter is not required to warn you.
"AWD" on the sticker is not the whole test
All-wheel drive still needs 3/16-inch tread on all four tires to comply, and it does not exempt you from the Chain Law when Code 16 is active. Nor does it change stopping distance on ice — all-wheel drive helps you go, not stop.
Chains are not a practical plan for visitors
Fitting chains correctly on the shoulder of I-70, in the dark, in a storm, at 11,000 feet, having never done it, is not a realistic backup. Our chauffeurs carry chains and know how to fit them; that is a professional skill, not a rental add-on.
The honest comparison
For many mountain trips, a private transfer costs less than a four-wheel-drive rental plus fuel, parking, and the risk. We lay the numbers out on the private car service vs. rental car page.
How do traction laws affect airport transportation?
They shape the vehicle we send
Any transfer that touches the I-70 mountain corridor between September and May goes out in a compliant AWD or 4WD vehicle on winter-rated tires with chains aboard — typically our Executive SUV (up to 5 passengers) or Luxury SUV (up to 6, and 5 between November 1 and April 30, when gear takes the sixth seat). We do not send a sedan up a pass in traction-law conditions.
They shape the schedule
Traction and chain restrictions slow the entire corridor, not just your vehicle. Winter DEN transfers get 60–90 minutes of buffer, and we plan mountain-to-airport pickups four hours before a domestic departure rather than the usual three. Timing detail is in our I-70 winter travel guide.
They occasionally cancel a trip
When CDOT escalates past the Chain Law to a closure, no compliant vehicle gets through. We tell you early, and our cancellation and rescheduling terms are published on the pricing and policies page.
What compliance looks like at Arion
AWD/4WD vehicles on winter-rated tires, chains carried, chauffeurs trained on grade and ice, Colorado PUC authority LL-04689, and full commercial auto and general liability coverage on every trip.
Frequently Asked Questions
What does Colorado's traction law require?
Four-wheel or all-wheel drive, or winter-rated (mountain-snowflake) or mud-and-snow (M+S) tires, with at least 3/16-inch tread depth on all tires. Any vehicle can also comply by carrying and using chains or an approved alternative traction device.
When is the traction law in effect on I-70?
Every year from September 1 through May 31 on I-70 between Dotsero and Morrison, whether or not it is snowing. CDOT can also activate it on any state highway during a storm.
Does a two-wheel-drive car ever comply with the traction law?
Not on tires alone. Under SB25-069, a two-wheel-drive vehicle must carry chains or an approved alternate traction device from September 1 through May 31, and they must be installed on at least two drive tires whenever the Traction Law is active. Upgrading to winter or all-season tires does not make a 2WD vehicle compliant.
Does my rental car comply with the traction law?
Often not. Standard rentals are two-wheel drive on all-season tires, frequently below 3/16-inch tread. All-wheel drive still needs adequate tread and does not exempt you when the chain law is active.
How does the traction law affect my airport transfer?
Any winter transfer touching the I-70 mountain corridor goes out in a compliant AWD or 4WD vehicle on winter-rated tires with chains aboard, and we add 60–90 minutes of schedule buffer for restricted conditions.
Do I need AWD to get to Breckenridge or Vail?
You need AWD/4WD or compliant winter tires with 3/16-inch tread from September through May on I-70. Our mountain vehicles meet or exceed the requirement and carry chains.
Where can I check for active traction or chain restrictions?
CDOT's COtrip.org lists active restrictions by highway segment, with live cameras. Overhead message signs along I-70 show current status, which can change within an hour.
What happens if the road closes entirely?
No vehicle is compliant with a closure. We monitor CDOT, tell you early, and work the alternative — reschedule, overnight, or return to Denver. Rescheduling terms are on our pricing and policies page.
What happens if Colorado's traction law is in effect?
Nothing changes for you. Our vehicles meet Colorado's traction law requirements as they sit, so there is no swap, no surcharge and no scramble the morning of your trip. On vans and buses your chauffeur may pull over to fit chains when conditions call for it. It takes a few minutes, and it is the reason the trip keeps moving while other vehicles are turned around at the checkpoint.
Planning Resources
Sources
Regulations, figures, and schedules on this page come from the operators and agencies that publish them. Check them yourself:
Skip the tire inspection. Book the ride.
Compliant vehicles, chains aboard, chauffeurs who know the pass.
Last reviewed: September 13, 2026 by Arion dispatch. Rates, policies and Colorado Department of Transportation rules are subject to change; call (970) 703-4995 for current details.