A trip that begins on dry pavement in Phoenix can reach snow, ice, and poor visibility near Flagstaff. Check the entire route on I-17 or I-40 before departure; weather in the Valley does not establish conditions in northern Arizona.
Use AZ511 for closures, restrictions, incidents, and highway cameras. National Weather Service Flagstaff provides winter forecasts and highway snow profiles. Identify legal truck parking before entering the high country and recheck conditions during safe stops.
Pre-trip preparation is your first line of defense
Inspect the essentials
Check tires, brakes, lights, wipers, winter washer fluid, heater, defroster, and exhaust system. Remove snow and ice from windows, mirrors, steps, and handholds. Follow the manufacturer's cold-weather maintenance and air-system procedures for your truck; equipment and drain arrangements differ.
Review the winter-operation section of the Arizona CDL manual with your instructor or carrier. Resolve defects before departure rather than waiting for freezing conditions to expose them.
Carry the right gear
Prepare for a closure or extended delay. ADOT recommends water, food, warm clothing, blankets, a flashlight, an ice scraper, and a charged phone. Carry needed medication and a charger, and plan sufficient fuel for delays and an alternative stopping location.
Check chain requirements for the route
Arizona's tire-equipment statute permits suitable chains when needed for safety because of snow, ice, or other skid-producing conditions. That permission does not establish a blanket winter chain-carry mandate for every commercial truck in Arizona.
Check current route restrictions and posted requirements, including those in other states on your trip. Follow your carrier's equipment policy. If chains may be needed, confirm they fit and learn installation in a safe training setting before the trip.
Adjusting your driving habits
Reduce speed and increase following distance
Reduce speed for traction and visibility, and leave more room ahead. FMCSA advises adjusting following distance for weather, road conditions, visibility, and traffic. No fixed number of seconds guarantees adequate stopping room on ice.
Avoid abrupt steering, acceleration, and braking. Know the truck's braking systems before entering winter conditions. The Arizona CDL manual warns against engine-brake or retarder use on slippery surfaces because drive-wheel braking can cause a skid; follow the vehicle's operating instructions and carrier training.
Skid response depends on which wheels have lost traction and the vehicle's systems. Learn the applicable procedures with qualified instruction rather than relying on one recovery sequence for every slide.
Recognize possible black ice
Ice can be hard to see, particularly on bridges and overpasses. A surface that looks wet may be frozen. Treat a loss of tire spray or ice on exposed equipment as warning signs, not a reliable test that the road is safe elsewhere.
Know when to park it
ADOT urges drivers to delay travel during winter storms. Give snowplows room and avoid passing a plow that is clearing the highway.
Choose a safe legal stopping location before visibility or traction becomes unmanageable. Avoid using the shoulder as planned parking. Communicate delays to dispatch early and follow closures.
Federal hazardous-condition rules require reduced speed and discontinuing operation when conditions become sufficiently dangerous, until the vehicle can be operated safely. A delivery appointment does not change that requirement.
