Winter driving in Colorado
Updated September 27, 2026
Colorado’s chain law requires commercial trucks to carry chains from September 1 to May 31. It covers vehicles over 16,000 pounds combined that are used in commerce, and vehicles that carry 16 or more people.
When the Commercial Vehicle Chain Law is in effect, you chain four drive tires, or all of them if you have fewer than four. The fine is up to $500 plus a $79 surcharge, and $1,000 plus a $157 surcharge if you get stuck and block the road.
Is the chain law on right now? This page explains the rules. For today’s roads, check COtrip.org or the overhead signs on your route.
Our home base is in the Denver area, so our drivers run these passes all winter. Here is what the law asks of a truck driver, where it applies, and how to be ready before the signs light up.
Who Colorado’s Chain Law Covers
The law is written for commercial motor vehicles, or CMVs. The Colorado State Patrol says you are a CMV if either one is true:
- Your truck, or truck and trailer together, weighs more than 16,000 pounds and is used in commerce on public highways.
- Your vehicle carries at least 16 people, counting the driver.
Every loaded car hauler is well past that weight, so the law applies to you. So does a pickup pulling a hotshot trailer that meets the weight line.
The name says “commercial,” but the State Patrol says the chain law turns on the weight rating, not the use. A big motorhome can fall under it too.
When It Applies: Dates and Roads
Chain season runs September 1 to May 31. For those months, a CMV must carry chains or approved traction devices on these mountain routes, whatever the weather:
| Route | Where chains must be aboard |
|---|---|
| I-70 | West of milepost 259 (Morrison) to the Utah line |
| CO 9 | Milepost 63 to 97 (Frisco to Fairplay) |
| US 40 | West of milepost 256 (Empire) to the Utah line |
| US 50 | West of milepost 225 (Salida) to the Utah line |
| US 160 | West of milepost 304 (Walsenburg) to the New Mexico line |
| US 285 | From milepost 250 (Morrison) to the New Mexico line |
| US 550 | The whole route |
This is newer than many drivers think. Carrying chains used to be required on part of I-70 only. A 2024 state law, Senate Bill 24-100, spread the rule to all seven routes.
Carrying chains is one rule. Putting them on is another.
CDOT can call the chain law on any state highway when a storm hits. On I-70, the must-carry rule covers the whole mountain stretch from Morrison, just west of Denver, to Utah.
Traction Law vs Chain Law
Colorado has three winter restrictions. Only one of them sets the rules for your truck.
- Passenger Vehicle Traction Law For cars and light trucks. Two-wheel-drive cars need chains or an approved device on the drive tires. Four-wheel and all-wheel drive cars can use winter-rated tires with enough tread.
- Passenger Vehicle Chain Law Every passenger vehicle needs chains or an approved device. CDOT calls this the last step before it closes the road.
- Commercial Vehicle Chain Law Your rule. Chains or approved devices go on all drive tires, up to four. It is based on weight, so it covers any rig over the line.
How you find out: CDOT posts the restriction on overhead message signs and roadside signs. It also sends it out through COtrip.org, phone messages, email, and text alerts. The notices say which mileposts and exits need chains.
Chain Law Fines in Colorado
The State Patrol lists two penalty levels for breaking a winter driving restriction:
- Up to $500, plus a $79 surcharge, for not following the restriction.
- $1,000, plus a $157 surcharge, if you get stuck and block any lane of the road.
CDOT’s freight fact sheet also lists a separate, smaller fine for not carrying chains on the must-carry routes. A stuck truck also costs you the day, and it can hold up everyone behind you.
Know the mountain rules? Run Rocky Mountain freight with Accelerated.
Chaining Up a Car Hauler
Car haulers get their own line in the State Patrol’s rules, under “auto transporters.” You chain four drive tires. The State Patrol lists these as ways to comply:
- 4 tire chains
- 4 AutoSocks
- Auto chains
- Sanders
Do not use chains if they would put your hydraulic lines at risk of damage. An approved alternative traction device may be used to lower that risk. If your rig cannot chain at all, the State Patrol says your travel will be restricted.
A few more rules that matter on a loaded rig:
- Trailers do not need chains. The rule covers drive tires.
- Clip-on chains do not count. An alternative device must be on CDOT’s Approved Product List.
- While the chain law is on, trucks stay in the right lane. You may pass a stalled or slower vehicle only if you can do it safely without losing traction.
- Chains stay on until CDOT says the chain law is over, or until you can see the centerline or lanes on a downhill grade.
About tire cables: the State Patrol’s list and CDOT’s freight handouts do not describe cables the same way. If you plan to run cables, confirm with CDOT’s freight office before you count on them.
Before You Head Over the Pass
Do this before you leave the yard, not at the chain-up area with snow blowing sideways.
- Check the chains are aboard. Four drive-tire chains or approved devices, in working shape, from September 1 on.
- Check COtrip before you roll. Look at the chain law status and road reports for your whole route, not only the first pass.
- Know your chain-up spots. CDOT lists chain stations on I-70, US 40, US 285, US 550, and other routes. Pick yours before you need one.
- Look at your hydraulic lines. Know where your chains sit near them. If chains would put them at risk, carry an approved device.
- Plan your hours around the pass. Chaining up and waiting out a closure take time. Leave room in your day so you do not run out of hours on the mountain.
Winter delays also eat into your hours of service. Our guide to hours of service for car haulers covers the 14-hour window and the adverse driving conditions rule.
Driving Out of Denver With Accelerated
Denver is Accelerated’s home base. Our yard sits in nearby Parker, Colorado. From here, our drivers run rail-head and regional lanes across the Rocky Mountain region, moving vehicles for the automakers.
Accelerated does not sell or assign lanes. Our drivers run over the road, and the lanes described here are examples of the freight we move from this area. See car hauler jobs out of Denver for the details.
Haul Cars Out of Denver
We hire drivers with 3 years of CDL-A driving and 1 year of verifiable 9-car experience. All of our contract drivers keep 82% of the truck’s gross. See car hauler jobs at Accelerated, or start your application now.
The application takes a few minutes from your phone.
Colorado Chain Law FAQs
When is chain season in Colorado?
September 1 to May 31. During those months, commercial trucks must carry chains or approved traction devices on the state’s mountain routes, including I-70 west of Morrison.
Do car haulers have to chain up in Colorado?
Yes. When the Commercial Vehicle Chain Law is in effect, auto transporters chain four drive tires. The State Patrol says not to use chains if they would put hydraulic lines at risk; an approved alternative traction device may be used instead, and a rig that cannot chain will have its travel restricted.
Do trailers need chains in Colorado?
No. CDOT says chains are not required on trailers. The chain law covers the drive tires.
What is the fine for breaking the chain law?
The Colorado State Patrol lists up to a $500 fine plus a $79 surcharge. If you get stuck and block any lane of the road, the fine is $1,000 plus a $157 surcharge.
How do I know if the chain law is on today?
Check COtrip.org, CDOT’s travel site. CDOT also posts the restriction on overhead and roadside signs and sends phone, email, and text alerts. The notices name the mileposts and exits where chains are required.
When can I take my chains off?
When CDOT announces the chain law is over, by sign or other notice, or when you can see the centerline or lanes on a downhill grade.
Sources
Last checked September 27, 2026. Rules and fines change. Confirm the current rules with the Colorado State Patrol or CDOT before you drive. This guide is a plain-language summary, not legal advice.