Winter Driving Safety
Driving in mountain regions during winter conditions requires planning and preparation to avoid hassles on the road and once you arrive at your destination.
Firstly, avoid traveling during a storm, whether it be rain, snow, or heavy wind and fog. These are not favorable driving conditions and can lead to problems along your route.
Is it imperative that you check road and weather conditions before you travel so you know if conditions are favorable or not favorable. Even in sunshine weather you must carry the appropriate equipment - tire chains, snow shovel, kitty litter, carpeting - should you need to install chains, dig out of a berm, or create traction.
Download the Caltrans Quickmaps app for your device to follow road and traffic conditions and chain requirements.
Please review our Winter Precautions and Planning page for info on making activity and lodging plans.
Tire Chain FAQs
When do I need chains?
You must stop and put on chains when CalTrans mandates it. Highway signs will indicate that chains are required. Checkpoints will not allow you to pass unless you abide by the mandate.
DO NOT STOP IN THE MIDDLE OF THE ROAD TO INSTALL CHAINS. YOU MUST PULL OVER AND OUT OF THE WAY OF TRAFFIC.
You can be cited by the California Highway Patrol and fined if you don't comply with chain requirements. Remember that restrictions are for your safety as well as other drivers'.
Chain Installers: If you use the services of a chain installer, be sure to get a receipt and jot the installer's badge number on it. Remember, chain installers are independent business people, not Caltrans employees. Having the badge number may help with any misunderstandings later. Chain installers are NOT allowed to sell or rent chains.
How do I find the right chains for my tires?
Check your vehicle owners manual and your tires for specifications on tire chains. It’s important to buy chains or other traction that are the correct size for your tires. Link-type chains that are too big will bang against the body your vehicle causing significant damage. Chains and other traction that are too small won’t fit around the tire at all.
Driving with Chains
The speed limit when chains are required is 25 or 30 miles an hour.
WHEN INSTALLING CHAINS, DO NOT STOP IN THE MIDDLE OF THE ROAD TO INSTALL CHAINS. YOU MUST PULL OVER AND OUT OF THE WAY OF TRAFFIC.
Once you leave the mountain region under chain control, you may remove tire chains. When removing chains, drive beyond the signs reading "End of Chain Control" to a pull-off area where you can safely remove them.
Where Can I Buy Chains?
Chains are sold at most auto supply shops, hardware stores, and some convenience stores. Call ahead to check what types of traction devices they carry. Please note, most stores are final sale only and do not rent chains.
Can studded tires and snow tires replace the need to carry/install chains?
No. Though studded tires are legal in California from Nov. 1 until Apr. 30 each year, studded tires are not considered tire traction devices and may not be used in lieu of chains.
Snow tires have the designation “Mud & Snow” or an abbreviation such as “M-S,” “M+S,” or “M/S” marked on the tire sidewall. Same as studded tire, snow tires may not be used in lieu of chains.
My car rental company won’t let me put chains on. Am I excused from carrying/wearing chains?
Many car rental companies may not allow chains on their inventory for various reasons, however this does not excuse you from carrying them or installing them if Caltrans requires it. The best bet if you’re worried about snowy roads is to rent either an all-wheel drive or 4-wheel drive vehicle for your journey.
I have a 4-Wheel/All-Wheel vehicle and I’m towing a trailer. Do I need chains?
You need to use chains if you’re towing a trailer. If the trailer has brakes, you must have at least one axle chained.
Chain Control Levels
Chain control coding is as follows:
- W: No Restrictions - Watch for snow on pavement.
- R-1: Chains are required on all commercial vehicles (trucks or buses). All other vehicles (cars, pick-ups, vans, etc.) must have either snow tread tires or chains on the drive axle.
- R-2: Chains are required on all vehicles except four-wheel drives with snow tread tires. Four-wheel drive vehicles must carry chains in the vehicle.
- R-3: Chains required - ALL VEHICLES - no exceptions.
Prepping to Drive
- YOU MUST CARRY CHAINS IN YOUR VEHICLE AT ALL TIMES DURING WINTER!
- Carry a sturdy shovel and cat litter - or gravel - should you need to dig out of a berm or create additional traction on icy roads.
- When driving during or shortly after a storm, expect delays. Plan on leaving extra early to manage heavy/slow traffic.
- Check road conditions before you drive and choose the route with the most favorable conditions.
- Make sure your tires have good tread and are properly inflated.
- Carry emergency supplies including: food, water, warm clothing, blankets, medication and a cell phone in case you become stranded.
- Caltrans crews work continuously to keep roadways clear for travelers. Please be patient and courteous while crews work.
- You can follow road conditions on Caltrans Quickmaps.
- Download the Caltrans Quickmaps app for your device.
Driving in Icy/Snowy Conditions
- Make sure you can see out of all windows of your vehicle.
- DO NOT POUR HOT WATER ON WINDOWS TO MELT ICE! Use an ice scraper and your defroster.
- Use your fog lights when driving in fog, rain, and snowstorms.
- Keep 3 car lengths away from the vehicle in front of you. The distance needed to stop on ice is twice as long as you would normally need to brake.
- NEVER brake suddenly or harshly while driving on ice – tap brakes lightly, on and off until you slow.
- Black ice can stay on roadways even in warmer conditions. Be careful when driving into shady areas and slow your vehicle on approach.
- Reduce your speed before you approach a turn. Avoid sudden acceleration or deceleration.
- Travel slowly, turn slowly, and brake slowly. Sudden swerving and braking will cause you to skid.
- If you do skid, slowly let off the accelerator, until you feel your wheels regain traction – do not brake!
- As you regain traction, turn the steering wheel in the direction you want to go. If you're still skidding, counter-steer and apply the gas lightly until your vehicle is pointing in the right direction.
- Be aware of your surroundings, including other drivers that may be losing control on the roadway.
- Slow down in icy/snowy/foggy conditions.
- When driving uphill on an icy road, you will need momentum. Slowing can cause you to slide backwards into traffic behind you.
- If you are nervous or inexperienced driving in winter conditions, avoid traveling and wait until conditions improve before venturing to the mountains.
When You Need Chains
- YOU MUST CARRY CHAINS IN YOUR VEHICLE AT ALL TIMES DURING WINTER!
- Caltrans will determine if tire chains are required. Check chain requirements on Caltrans Quickmaps.
- R2 conditions require 2-wheel vehicles to wear chains. R3 conditions require ALL vehicles to wear chains. There are no exceptions to these rules.
- Caltrans checkpoints will not allow you to pass if you do not abide by chain requirements.
- DO NOT STOP IN THE MIDDLE OF THE ROADWAY TO PUT CHAINS ON.
- You must install the chains on the drive tires. Refer to your vehicle manual if you are unsure of which wheels are your drive tires.
- Carry a shovel, rubber mats, cat litter or other materials to help with traction if you get stuck.
- See Tire Chain FAQs