Severe Weather Driving for Commercial Drivers

Bad weather is where a heavy truck's size turns against you. A rig that handles well on a dry road can jackknife on black ice, tip over in a crosswind or vanish into a fog bank at highway speed. No load is worth that. The most important skill here is knowing when to stop.

You already know how to adjust for rain, ice and darkness in any vehicle. This goes further, into how the rules apply to a truck, how you make the call to stop, and what to do when a combination vehicle starts to lose grip. Handling a skid is a hands-on skill, so practice it with a qualified instructor, ideally on a skid pad or simulator. Reading alone does not build it.

What You Will Be Able to Do

• Apply the federal hazardous conditions rule to a go, slow or stop decision.
• Set speed and following distance for the conditions, using real numbers.
• Recognize and respond to skids and a starting jackknife.
• Judge wind risk, especially for empty or light trailers.
• Follow chain laws, and protect a stopped truck with warning devices.

The Rule That Governs It All

Under 49 CFR 392.14, you must use extreme caution in conditions that reduce visibility or traction, such as snow, ice, sleet, fog, mist, rain, dust or smoke. You must reduce speed. And if conditions become dangerous enough, you must stop, and you may not start again until the vehicle can be driven safely. The only exception is when stopping would make things more dangerous for your passengers, in which case you may go on to the nearest safe point.

In other words, the law expects you to park. A delivery time does not change that. If you crash at a legal speed in a storm, 392.14 is the rule you will be asked about, because a speed limit is set for good conditions.

The Go, Slow or Stop Decision

Decide before you are in trouble. Review it at every stop, and again whenever conditions change.

Then choose.

• Go when the road is clear and the forecast holds for the time you will be out in it.
• Slow when traction or visibility has dropped, but you can still stop within what you can see.
• Stop at a safe place when you cannot see far enough to stop, when your tires are losing grip, or when other trucks are parking or sliding off.

Stop early, while you can still choose a safe place. The shoulder of a highway in a whiteout is one of the most dangerous places you can be. Tell your dispatcher, note why, and do not let anyone talk you back onto the road.

Worked Example: Reading a Plan

You have 6 hours of driving left, and 300 miles to go. A winter storm warning starts along your route in 4 hours. Roads are clear now, and a truck stop sits 180 miles ahead.

At 50 mph, 180 miles takes 3.6 hours, so you reach the truck stop before the storm. If you press on, you would be on the road in the worst of it for 2 hours. Your plan: drive to the truck stop, get a spot before they fill up, check the road conditions, and tell your dispatcher now that you expect to be late.

Remember that a forecast storm does not qualify for the adverse conditions extension, since you knew about it.

Setting Speed and Space

CDL manuals give these starting points. They are a guide, not a safe limit.

Space matters as much as speed. In good conditions over 40 mph, you need one second for each 10 feet of vehicle length, plus one second.

Worked example: A 70-foot rig needs 7 + 1 = 8 seconds on a dry road. On a wet road, a common rule is to double that, so you need about 16 seconds. On snow, you need far more. At 40 mph you cover about 59 feet a second, so 16 seconds is about 940 feet of space. Gaps much shorter than that are how pile-ups start.

Do not use cruise control on a wet, snowy or icy road. Do not use the engine brake or retarder on a slick road either. When your drive wheels have poor traction, a retarder can make them skid, and CDL manuals say to turn it off on wet, icy or snow-covered roads. Check the owner's manual and your carrier's policy.

Watch the road surface. When the spray from the truck in front of you stops, the water has turned to ice. Look for ice on your mirror arms, antenna or wipers, as that tells you the surface may be freezing too. Bridges freeze first.

Skids and Jackknifes

Most serious skids come from too much speed for the surface, and from over-braking, over-steering or over-accelerating. Smooth driving prevents most of them.

Countersteer as the truck comes back, so you do not start a skid the other way. Early correction matters. If the trailer swing has gone past a small angle, you may no longer be able to save it, so stay focused on keeping the tractor pointed where it is safe.

An empty or light trailer skids more easily, because there is little weight on its tires. Many drivers expect a heavy load to be the risk in winter. Empty trailers are often worse.

Wind

High winds can blow over a truck. Empty and light trailers, high-sided vans and tall reefers are most at risk.

• Empty trailer. With little weight holding it down, a strong crosswind can tip it. Slow down, or park.
• Exposed ground. Open plains, high bridges and mountain passes are the worst places. Gusts hit as you come out from behind a cut, a hill or an overpass.
• Posted warnings. Some states close roads or bridges to empty or light high-profile vehicles when winds reach set levels. Those limits vary, so check them. They apply to you.
• Heavy loads. Load weight helps with tipping, but a heavy truck can still be pushed across a lane.

If you feel gusts pushing the trailer, keep a firm grip, slow down, and find a place to stop. Point the truck into the wind if you can, so the gusts do not hit the side of the trailer, and do not park where you will block a road or where a trailer could tip onto someone.

Fog, Dust and Smoke

Fog and dust cut visibility all at once, and they lead to multi-vehicle crashes. CDL manuals give the best advice for fog in one word: don't. If you can, pull into a rest area or truck stop until you can see. If you are caught in it:

1. Slow down before you enter it.
2. Use low beams and fog lamps. High beams reflect back at you.
3. Turn on your four-way flashers so that drivers behind you see you sooner, unless your state's rules say otherwise.
4. Keep your speed low enough to stop within the distance you can see.
5. If you must stop, get completely off the road, well clear of the travel lanes. Do not stop in a lane.

Many of the worst crashes begin when a truck stops in a lane and the next vehicle cannot see it.

Chains and Chain Laws

Chain laws vary from state to state, and from road to road within a state. They can change with each storm. Some states have minimum tire tread rules, and some list which axles must be chained. Know the law before you enter that state, and check your state DOT's alerts.

1. Find out the rules for your route, and carry the chains the law asks for, when your route calls for them.
2. Practice fitting chains in a dry yard, not on a shoulder in a storm.
3. Stop at a marked chain-up area. Do not stop in a traffic lane. Wear high-visibility clothing, as well as gloves.
4. Lay out the chains, fit them as the chain maker says, drive forward a little, and retighten them.
5. Keep to the chain maker's speed limit, often 25 to 30 mph.
6. Remove them when the rules allow, and inspect them.

Warning: Chaining up puts you on foot next to traffic that may be sliding. Use a marked area, wear high-visibility gear, keep your flashers on, and stay on the side away from traffic if you can.

Do not head out if you cannot legally continue. Fines for ignoring chain laws can be heavy, and blocking a mountain road with a spun-out truck can bring more.

Extreme Heat

Heat is a quieter hazard, but it destroys tires, engines and brakes.

• Tires. Inspect them every 2 hours or every 100 miles in very hot weather. Air pressure rises as they heat up. Do not let air out, or the pressure will be too low when the tires cool. A tire that is too hot to touch needs to cool down first. Stop until it does, or it may blow or catch fire.
• Engine. Watch the temperature gauge. Check coolant and belts. Do not open a radiator cap on a hot engine.
• Brakes. Hot days make brake fade more likely on a long grade.
• Road surfaces. Tar can bleed to the surface and make a road slick.
• You. Drink water, and do not spend your break in a hot cab, because heat makes you tired.

When You Are Stopped on the Road

If you stop on the road or shoulder for anything other than a necessary traffic stop, 49 CFR 392.22 sets what you must do. Turn on your four-way flashers at once. You must place warning devices as soon as possible, and within 10 minutes.

Watch for vehicles that lose control while you place them. If your load leaks flammable liquid or gas, do not use a flare or any other flame near it.

Stranded in the Cold

If you have to wait out a storm, stay with the truck. Keep the exhaust clear of snow, because a blocked exhaust can push carbon monoxide into the cab. Carry warm clothes, water, food, a flashlight, a charger and a first aid kit. Keep the fuel tanks well up in winter. Tell your dispatcher where you are and how you are doing.

Common Mistakes

Check Your Understanding

1. It is snowing hard, and you can see only about 200 feet. You feel safe at 45 mph, and your delivery is due. What does 392.14 say? Reduce speed and use extreme caution. If it is too dangerous, you must stop. At 45 mph you cannot stop within 200 feet, so slow down a lot or park.
2. Your empty trailer starts rocking in crosswinds on a high plain, and a wind warning is posted. What do you do? Slow down, and get off at the next safe place until it passes. An empty trailer can tip.
3. Your trailer starts to swing out on ice as you brake. What do you do? Release the brakes so the trailer tires can grip again, and steer smoothly. Do not use the trailer hand valve.
4. You break down on a two-lane road at night. What must you do, and by when? Turn on your flashers at once and place your warning devices within 10 minutes, at about 10 feet and 100 feet toward oncoming traffic, and 100 feet the other way.
5. On a very hot day, you find a tire far hotter than the others at a stop. What do you do? Stop until it cools, find out why, and do not let air out. It could be under-inflated, or a brake could be dragging.

Key Takeaways

• Under 392.14, you must slow down in poor conditions and stop if it is too dangerous.
• Decide early, while you can still reach a safe place.
• Reduce speed by a third on wet roads and by half or more on snow. Crawl on ice and get off the road.
• Keep retarders and cruise control off on slick roads.
• Empty trailers skid and tip more easily.
• Know the chain law for your route, and place warning devices within 10 minutes.