Winter Car Kit for I-70: What to Carry and What the Traction Law Requires
If you drive I-70 into the mountains between fall and spring, a little preparation changes a bad day into an inconvenience. Here is a practical kit, and a summary of Colorado's traction law with links to the official source, since the rules were recently updated.
Colorado's Passenger Vehicle Traction Law in brief
- Where and when: on I-70 between Dotsero and Morrison, from September 1 through May 31, the traction law can be put into effect when conditions require. CDOT can also use traction and chain laws on other state highways.
- How you will know: overhead signs, COtrip alerts, and CDOT's roadway condition notices.
- What counts: according to CDOT and Colorado State Patrol, passenger vehicles need tires with at least 3/16 inch of tread that carry a mountain-snowflake, M+S, M&S, M/S or all-weather rating, or chains or an approved alternative traction device on drive tires. Colorado State Patrol says two-wheel-drive vehicles must carry chains or an approved device from September 1 to May 31. Because the law changed in 2026, a car being AWD or 4WD does not by itself satisfy the requirement.
- Chain law: in severe storms CDOT can move to the passenger vehicle chain law, which requires chains or an approved device on every vehicle. It is the last step before the highway is closed.
- Penalties: failing to comply can bring fines and surcharges, and larger penalties if your vehicle blocks the road and causes a closure. CDOT lists the current amounts on its traction-law page.
Official sources: CDOT: Passenger Vehicle Traction and Chain Laws · Colorado State Patrol: Chain Law Information.
Check your tires first
The best winter kit is a good set of tires. Check the tread depth (a quarter placed upside down in the groove is a rough check, but a tread gauge is better), look for the mountain-snowflake or M+S marking on the sidewall, and make sure the pressure is right. Cold air lowers tire pressure, so check it on a cold morning.
What to keep in the car
| Must carry | Why |
|---|---|
| Tire chains or an approved traction device, and know how to put them on (practice at home) | May be required, and installing in a snowstorm is hard if you have never done it. |
| Warm blanket, gloves, hat, extra jacket | A car cools down fast once the engine is off. |
| Ice scraper and snow brush | Clear the whole car, including the roof and lights. |
| Portable jump pack or jumper cables | Cold kills batteries. See how to jump-start a car. |
| Phone charger and a charged power bank | Your phone is your lifeline for traffic alerts and calling help. |
| Flashlight (and spare batteries), reflective triangles or flares | Be seen at night and in whiteouts. |
| Water and non-perishable snacks | I-70 closures can last hours. |
| Small shovel, traction mats or sand/cat litter | For getting unstuck from soft snow. |
| Basic first-aid kit and any medications you need | For small injuries and long waits. |
| Washer fluid rated for cold weather | Salt and mag chloride spray is constant on the corridor. |
Habits that help
- Keep the tank at least half full in winter. If you are stuck, you may need to run the heater.
- Check COtrip.org or call 511 before you go, and leave extra time. Many drivers get stuck because of other crashes, not their own car.
- Slow down and leave space. Plows and tow trucks need room.
- Move over or slow down for stopped emergency and tow vehicles, as Colorado law requires.
- If you get stuck: stay with the car, keep the exhaust pipe clear of snow if you run the engine, run it only briefly for heat, and call 911 in an emergency. For non-emergency state patrol help from a cell phone in Colorado, dial *277.
What ShoulderCrew can and cannot do
A ShoulderCrew helper can bring a jump pack, change a flat, unlock a door or deliver fuel in the Denver area. We do not provide towing, and a membership is help on the spot, not reimbursement. In a mountain storm or a closed highway, follow CDOT and Colorado State Patrol instructions and call 911 if it is an emergency.
Want roadside help on your side before you need it?
ShoulderCrew is a membership for roadside help in the Denver area: jump starts, lockouts, flat changes and fuel delivery from local helpers, from $5.49/mo or $39/yr. It is help on the spot, not reimbursement, and towing is not included. We are launching in Denver first, and helper booking turns on as local helpers are verified, so join now to be first in line.
See membership plansSign up freeCommon questions
Does Colorado's traction law apply to AWD and 4WD vehicles?
Yes. CDOT and Colorado State Patrol say all passenger vehicles need qualifying tires (at least 3/16 inch of tread with a mountain-snowflake, M+S or all-weather rating) or chains/approved traction devices when the law is active. The 2026 changes mean AWD or 4WD alone does not satisfy the requirement. Check CDOT for current rules.
When is the Passenger Vehicle Traction Law in effect on I-70?
The law can apply on I-70 between Dotsero and Morrison from September 1 through May 31, and CDOT activates it when conditions require, shown by overhead signs and COtrip alerts.
What should be in a winter car kit for Colorado?
A warm blanket, gloves, an ice scraper, a jump pack, a phone charger or power bank, a flashlight, water and snacks, a small shovel, traction mats or sand, a first-aid kit, and tire chains or an approved traction device.
Sources: CDOT: Passenger Vehicle Traction and Chain Laws · Colorado State Patrol: Chain Law Information