Night Driving and Extreme Weather Conditions for CDL Drivers

Night driving and extreme weather are two of the most dangerous conditions a commercial driver faces. According to the FMCSA, crash rates increase significantly after dark and in adverse weather. This guide covers the specific techniques, rules, and procedures you need for the CDL written test and for staying alive on the road. Study these alongside our free CDL practice tests.

Night Driving: Rules and Safety Techniques

Driving at night is fundamentally different from driving during the day. Your visibility drops from thousands of feet to a few hundred feet, fatigue becomes a major factor, and other drivers may be impaired. Here's what you need to know:

Headlight Requirements

• Headlights must be on from sunset to sunrise
• Headlights must be on whenever windshield wipers are in use (in most states)
• Headlights must be on when visibility is less than 1,000 feet
• Headlights must be on in tunnels
• Use high beams on open roads when no vehicle is within 500 feet ahead
• Switch to low beams within 500 feet of an oncoming vehicle or when following within 300 feet of another vehicle
• Never drive with parking lights instead of headlights — they are not bright enough

Visibility at Night

With low beams, you can see approximately 250 feet ahead. With high beams, visibility extends to about 350–500 feet. At 55 mph, your truck covers 80 feet per second. That means with low beams, you have about 3 seconds to react to a hazard in your path. This is why reducing speed at night is critical.

Night Driving Safety Tips

1. Reduce speed. You should be able to stop within the distance illuminated by your headlights. If you can't, slow down.
2. Watch for pedestrians and animals. They're harder to see at night, especially on rural roads. Watch for eye reflections from animals.
3. Keep windshields and mirrors clean. Glare from oncoming headlights is amplified by dirt and film on glass. Clean your windshield inside and out at every fuel stop.
4. Dim dashboard lights. Bright instrument lights reduce your night vision. Dim them to the lowest readable level.
5. Avoid looking directly at oncoming headlights. Look to the right edge of the road to preserve your night vision.
6. Take breaks every 2 hours. Night driving increases fatigue. If you feel drowsy, pull over — do not push through it.
7. Use your headlights, not just daytime running lights. DRLs don't illuminate taillights, so vehicles behind you may not see you.

Driving in Rain and Wet Conditions

Rain is the most common adverse weather condition. It reduces traction, visibility, and brake effectiveness. Here's how to handle it:

• Reduce speed by 1/3. If the speed limit is 60 mph, drive no faster than 40 mph in heavy rain.
• Increase following distance to 8–10 seconds. Wet roads can double your stopping distance.
• Watch for hydroplaning. If your tires ride on top of water instead of the road, you have no traction. It can occur at speeds as low as 30 mph with worn tires. If you hydroplane, ease off the accelerator and steer straight — do not brake.
• Turn on headlights and wipers. In most states, this is required by law when wipers are on.
• Watch for spray from other vehicles. A truck ahead can throw a wall of water that temporarily blinds you.
• Be cautious after a dry spell. The first rain after a dry period makes roads especially slick — oil and rubber dust accumulate on the surface and create a slippery film.

Driving in Fog

Fog is one of the most dangerous driving conditions because it reduces visibility without warning. If you encounter fog:

• Slow down before entering fog. Don't wait until you're in it — by then you may not be able to see a stopped vehicle.
• Use low beams or fog lights — never high beams. High beams reflect off the fog and create a white wall, reducing visibility further.
• Increase following distance dramatically. You need enough space to stop if the vehicle ahead disappears into fog and turns out to be stopped.
• Listen for traffic. Roll down your window slightly and listen for engines, tires, or horns that you can't see.
• If visibility drops below 1/4 mile, consider exiting. Pull into a truck stop or rest area. Do not stop on the shoulder — it's a rear-end collision waiting to happen.
• Do not use hazard lights while moving. They can confuse other drivers into thinking you're stopped.

Winter Driving: Snow and Ice

Winter driving requires the most significant adjustments to your driving technique. Key rules:

• Reduce speed by at least 1/2 on snow-packed roads. On ice, reduce to the minimum speed that maintains control — sometimes 10–15 mph.
• Never use the Jake brake (engine brake) on ice or slippery surfaces. It can cause drive wheels to lock, triggering a skid.
• Make all inputs smooth and gradual. Accelerate gently, brake gently, steer gently. Sudden inputs break traction.
• Watch for black ice. It forms at 32°F or below and looks like dark, wet pavement. Bridges and overpasses freeze first because cold air circulates underneath them.
• Carry chains and know how to install them. Many mountain passes require chains during winter. Practice installing them before you need to.
• Maintain at least 10–12 seconds of following distance. On ice, you may need 12–14 seconds.
• If you skid, steer in the direction you want to go. Do not brake hard — that locks the wheels and extends the skid.

High Wind Conditions

High winds are especially dangerous for high-profile vehicles like tractor-trailers. Gusts can push your trailer into another lane or, in extreme cases, tip the vehicle over.

• Reduce speed significantly. Wind force increases with speed — driving slower reduces the effect.
• Keep both hands firmly on the wheel. Gusts can yank the steering wheel suddenly.
• Be extra cautious with empty trailers. An empty trailer is lighter and more susceptible to wind. A fully loaded trailer is more stable.
• Watch for open areas. Bridges, mountain passes, and open plains are where winds are strongest. Trees and buildings block wind, but when you exit a protected area into an open one, a gust can hit without warning.
• If winds exceed 40+ mph, consider parking. No delivery deadline is worth your life. Park the truck and wait for the wind to die down.

When to Stop Driving

The FMCSA gives you the right to stop driving in hazardous conditions without penalty. Under 49 CFR 392.14, a driver who reasonably believes that continuing would be dangerous may discontinue driving. Your carrier cannot force you to drive in unsafe conditions. Use this right when:

• Visibility is near zero (whiteout fog or snow)
• Roads are covered in ice and traction is minimal
• Wind gusts threaten to tip your trailer
• You are too fatigued to drive safely
• Flooding covers the roadway

For more on your legal rights and responsibilities, read our guide on CDL Hours of Service.

Frequently Asked Questions