Driving in Difficult Conditions - Complete Guide
Different driving conditions require different approaches for safe commercial vehicle operation. Sections 2.10-2.14 of the CDL manual cover aggressive driving, night driving, fog, winter weather, and hot weather—all frequently tested on the CDL exam. Understanding headlight ranges, ice indicators, and proper tire procedures is essential.
Aggressive Driving and Road Rage
Definitions
| Term | Meaning |
|---|---|
| Aggressive driving | Operating selfishly, boldly, or pushily without regard for others |
| Road rage | Operating with intent to harm others or physically assaulting drivers |
Don't Be an Aggressive Driver
- Reduce stress before and while driving
- Be realistic about travel time—expect delays
- Give other drivers the benefit of the doubt
- Stay in the right lane; don't block traffic
- Avoid gestures—keep hands on wheel
- If someone wants in front of you, let them
When Confronted by an Aggressive Driver
- Get out of their way—first priority
- Don't challenge them—put pride aside
- Avoid eye contact
- Ignore gestures—don't react
- Report to authorities if safe (vehicle description, license, location)
Night Driving
Why It's More Dangerous
- Less time to see hazards and respond
- Poor lighting on most roads
- More impaired drivers (especially after bar closing times)
- Fatigue affects most people at night
Headlight Visibility Ranges
| Light Type | Visibility Distance |
|---|---|
| Low beams | 250 feet |
| High beams | 350-500 feet |
Critical Rule: Adjust speed so you can stop within your headlight range. If you can't stop within the distance you can see, you're going too fast.
When to Dim Headlights
Dim your lights within 500 feet of:
- Oncoming vehicles
- Vehicles you're following
Avoiding Glare
- Don't look directly at oncoming headlights
- Look slightly to the right at lane marking or road edge
- Don't retaliate with high beams—increases danger for everyone
- Keep windshield and mirrors clean (dirt creates glare)
- Don't use tinted lenses at night
- Keep cab interior dark—dim instrument lights
Fatigue Facts
| Statistic | Value |
|---|---|
| Crashes involving drowsy driving | 100,000/year |
| Drivers who've felt sleepy while driving | 60% |
| Drivers who've fallen asleep at wheel | 36% |
| Heavy truck crashes involving fatigue | At least 15% |
| Sleep needed for alertness | 8-9 hours |
Fatigue Warning Signs
- Difficulty focusing, heavy eyelids
- Yawning repeatedly
- Can't remember last few miles
- Drifting from lane
- Missing exits or signs
- Feeling restless or irritable
Only Safe Cure: Stop and sleep. A 15-20 minute nap can save lives.
High-Risk Times
- Midnight to 6 a.m.
- Mid-afternoon
Driving in Fog
Best Advice
Don't drive in fog. Pull into rest area or truck stop until visibility improves.
If You Must Drive in Fog
| Do | Don't |
|---|---|
| Obey fog warning signs | Assume fog will thin out |
| Slow down BEFORE entering fog | Use high beams (reflects back) |
| Use low beams and fog lights | Pass other vehicles |
| Turn on 4-way flashers | Stop on roadside unless emergency |
| Use roadside reflectors as guides | Trust taillights ahead (vehicle may be off road) |
| Listen for traffic you can't see |
Winter Driving
Pre-Trip Winter Checks
| Item | What to Check |
|---|---|
| Coolant | Level and antifreeze amount (use tester) |
| Defrosters/heater | Working properly |
| Wipers | Good condition, press firmly on glass |
| Washer fluid | Full, use antifreeze washer fluid |
| Tires | Adequate tread (4/32" front, 2/32" others) |
| Chains | Right number, correct fit, no broken parts |
| Exhaust system | No leaks (carbon monoxide danger) |
Signs of Ice on Road
- No spray from other vehicles (ice has formed)
- Ice on mirrors or wiper blades (road is likely icy too)
- Bridges and overpasses freeze first
- Melting ice is MORE slippery than frozen ice
Ice Check: If mirrors and wipers have ice, the road is probably icy.
Winter Driving Techniques
| Action | Why |
|---|---|
| Start gently and slowly | Get feel of road |
| Turn and brake gently | Prevent skids |
| Turn OFF retarder/engine brake | Can cause drive wheel skids |
| Don't pass unless necessary | Minimize lane changes |
| Increase following distance | Need more stopping room |
| Slow down as ice melts | Wet ice is more slippery |
Wet Brakes
Driving through deep water can cause:
- Weak brakes
- Uneven braking
- Grabbing brakes
- Wheel lockups
- Jackknife (with trailer)
Drying Wet Brakes
- Slow down, use low gear
- Gently apply brakes while crossing water (keeps water out)
- Increase engine RPM while maintaining light brake pressure
- After exiting water, keep light brake pressure to heat and dry brakes
- Test brakes when safe—check behind first
Hot Weather Driving
Tire Checks
Check tires every 2 hours or 100 miles in hot weather.
| Situation | Action |
|---|---|
| Tire pressure increases | Do NOT let air out |
| Tire too hot to touch | Stop and wait until it cools |
Critical: Never release air from hot tires. Pressure will be too low when tires cool, risking blowout.
Engine Monitoring
| Item | What to Watch |
|---|---|
| Oil temperature | Stay in proper range |
| Coolant temperature | Stay in normal range |
| Coolant level | Check regularly |
Adding Coolant to Hot Engine
Never remove radiator cap from hot pressurized system.
If no recovery tank:
- Shut off engine
- Wait until cooled
- Protect hands (gloves or thick cloth)
- Turn cap slowly to first stop (releases pressure)
- Step back while pressure releases
- Remove cap, check level, add coolant
- Replace cap securely
Safety Test: If you can touch radiator cap with bare hand, it's probably cool enough to open.
Hot Weather Hazards
- Bleeding tar—rises to surface, very slippery
- Tire blowouts—heat increases risk
- Engine overheating—drive slowly to reduce heat buildup
Frequently Asked Questions
Q: What is the visibility range for low beam headlights?
A: 250 feet. High beams provide 350-500 feet. You must adjust speed so you can stop within these distances.
Q: When should you dim your headlights?
A: Within 500 feet of oncoming vehicles and within 500 feet of vehicles you're following.
Q: What's the only safe cure for drowsiness?
A: Sleep. A 15-20 minute nap can save lives. Caffeine is temporary and not reliable.
Q: What lights should you use in fog?
A: Low beams and fog lights. High beams reflect off fog and reduce visibility. Also use 4-way flashers.
Q: How do you know if ice has formed on the road?
A: No spray from other vehicles, ice on your mirrors or wipers, and temperatures near or below 32°F. Bridges freeze before roads.
Q: Should you use the engine brake on icy roads?
A: No. Turn off retarders and engine brakes—they can cause drive wheel skids on slippery surfaces.
Q: How do you dry wet brakes?
A: Apply light brake pressure while crossing water, then maintain light pressure after exiting to heat and dry the brakes. Test when safe.
Q: How often should you check tires in hot weather?
A: Every 2 hours or 100 miles. Never release air from hot tires.
Q: What should you do if a tire is too hot to touch?
A: Stop and wait until it cools. Driving on an overheated tire can cause blowout or fire.
Q: What causes bleeding tar?
A: Very hot weather causes tar to rise to the road surface. These spots are very slippery.
Next Steps
Memorize the key numbers:
- Low beams: 250 feet
- High beams: 350-500 feet
- Dim lights: 500 feet from others
- Tire checks: every 2 hours or 100 miles in heat
Ready to test your knowledge? Start practicing with our Driving Conditions questions.