Federal rules that apply in snow and ice
- Slow down — or stop. When snow, ice, sleet or fog affect visibility or traction, the driver must use extreme caution and reduce speed. If conditions become dangerous enough, the driver must stop and not continue until it is safe. §392.14
- Up to 2 extra hours. A driver who runs into adverse conditions may drive up to 2 hours past the normal driving and on-duty limits to finish the run or reach a safe place. It only counts for conditions that weren't known — or couldn't reasonably be known — when the driver started the day or when the carrier dispatched the load. §395.1(b)(1), §395.2
- Tread. At least 4/32 inch on steer tires and 2/32 inch on all others. §393.75
- Emergency declarations. When a governor or FMCSA declares a regional emergency, hours-of-service and other safety rules in parts 390–399 are relaxed for up to 30 days — but only for drivers giving direct assistance to the relief effort, not for ordinary freight. §390.23; FMCSA final rule, Oct 5, 2026
Chain laws in the mountain states
| State | Source |
|---|---|
| Colorado Must Carry Law (2024): every commercial vehicle over 16,000 lb combined weight carries chains or an approved traction device September 1 – May 31 on more than 1,400 miles of highway — including I-70 between Dotsero and Morrison, CO 9 and parts of US 40, 50, 160, 285 and 550 — whatever the weather. Not carrying: $500. Stuck and blocking the road: up to $1,000 plus surcharge. | CDOT, Oct 21, 2025 |
| Washington Vehicles over 10,000 lb GVWR carry chains November 1 – April 1 on the listed mountain routes — I-90 Snoqualmie Pass, US 2 Stevens Pass, US 12 White Pass, SR 410 and others — plus at least two extra chains. Outside those dates, only when posted. | WSDOT; WAC 204-24-050 |
| Oregon Vehicles over 10,000 lb GVW or towing must carry and use chains when snow-zone signs say so. A tandem-drive truck chains two tires on each side of the primary drive axle (one per side on a single drive axle); combinations also chain trailer tires. Failing to carry and use them is a Class A violation for a commercial driver. | ODOT Commerce and Compliance |
| California Caltrans posts chain controls by level. R1: chains, traction devices or snow tires on the drive axle. R2: chains or traction devices on all vehicles except 4WD/AWD with snow tires. R3: chains on every vehicle, no exceptions. Vehicles towing trailers chain one drive axle, and a trailer with brakes chains one axle. | Caltrans chain controls |
Other states — Idaho, Montana, Wyoming, Utah, Nevada among them — post chain or traction requirements on specific passes when conditions require. Check the state's 511 service before a mountain route; the rules above are summaries, and posted signs always control.
Fleet checklist before the first storm
- Chains on every truck that runs Colorado, Washington or Oregon in season — the right size, enough for the drive axles, plus Washington's two spares.
- Tread checked on every steer and drive tire, and written up on the inspection report. §393.75, §396.11
- A written stop policy: drivers may park when conditions are dangerous, without penalty. That is what §392.14 requires, and juries ask about it.
- Winter training on file for every driver — chaining, following distance, when to stop. Training records were central to a $44.1M ice-storm pileup verdict in Texas in 2025.
- Adverse-condition time annotated in the log with what happened and where, so the extra 2 hours hold up in an audit. §395.1(b)
Winter-ready, on paper too
We keep inspection reports, training records and driver logs in one place, and flag what an auditor or a plaintiff's lawyer would ask for.
Sources: 49 CFR 390.23, 392.14, 393.75, 395.1(b), 395.2; FMCSA (Oct 5, 2026); Colorado DOT (Oct 21, 2025); WSDOT and WAC 204-24-050; Oregon DOT Commerce and Compliance Division; Caltrans. State rules change — check the state DOT before you travel. General information, not legal advice. IFTAX is not affiliated with FMCSA or any government agency.