Complete CDL Study Guide

Master all 7 sections of the CDL general knowledge test

📚 How to Use This Study Guide

  1. Read each section carefully
  2. Take notes on key numbers
  3. Test yourself with our practice test
  4. Have questions? See our CDL Permit Test FAQ
  5. Need a study plan? Read How to Pass the CDL Test First Try
  6. Review weak areas

Section 1: Vehicle Inspection

Pre-Trip Inspection

Perform thorough pre-trip inspection before every trip.

Seven-Step Method:

  1. Vehicle Overview - Check for damage, leaks
  2. Engine Compartment - Oil, coolant, belts
  3. Start Engine - Check gauges, controls
  4. Turn Off Engine - Check lights
  5. Walk-Around - Tires, brakes, suspension
  6. Signal Lights - All functioning
  7. Start Engine - Check brake system

Critical Items:

  • Tire tread: 4/32" front, 2/32" others
  • Air brakes: 100-125 psi
  • All lights working
  • Mirrors clean and adjusted

Section 2: Basic Control

Shifting and Speed

Shift at recommended RPM. Downshift before hills.

Backing Safely:

  • Get out and look (GOAL)
  • Back slowly
  • Use mirrors constantly
  • Sound horn
  • Back to driver's side when possible

Section 3: Braking Systems

Air Brake System

Critical Numbers:

  • Normal pressure: 100-125 psi
  • Low air warning: Before 60 psi
  • Emergency brakes: Below 20-45 psi
  • Pressure buildup: 85 to 100 psi in 45 seconds
  • Air loss: Max 3 psi/min (single) or 4 psi (combination)

Section 4: Safe Driving

Following Distance

One second per 10 feet of vehicle length under 40 mph.

  • 40-foot vehicle = 4 seconds minimum
  • Add 1 second above 40 mph
  • Add 1 second in bad weather

Night Driving:

  • Clean headlights and windshield
  • Reduce speed
  • Don't overdrive headlights
  • Watch for animals

Section 5: Cargo Securement

Weight Limits

  • Maximum gross: 80,000 lbs Interstate
  • Steer axle: 12,000 lbs max
  • Single axle: 20,000 lbs max
  • Tandem axle: 34,000 lbs max

Securement Rules:

  • Minimum 2 tie-downs up to 10 feet
  • Add 1 per additional 10 feet
  • Check within 50 miles of start
  • Re-check every 3 hours or 150 miles

Section 6: Hazardous Conditions

Weather Conditions

Rain:

  • Reduce speed by 1/3 on wet roads
  • Reduce by 1/2 in heavy rain

Ice and Snow:

  • Black ice at 32°F
  • Bridges freeze first
  • Reduce speed 50% or more
  • Don't use engine brake on ice

Fog:

  • Use low-beam headlights
  • Never use high beams
  • Pull over if visibility too poor

Section 7: Rules and Regulations

Hours of Service

  • 11-Hour Limit: Max 11 hours driving after 10 hours off
  • 14-Hour Limit: Can't drive beyond 14th hour on duty
  • Rest Break: 30-minute break after 8 hours driving
  • 60/70-Hour Limit: Max 60/70 hours in 7/8 days

Required Documents:

  • Valid CDL license
  • Medical certificate
  • Vehicle registration
  • Proof of insurance
  • Logbook/ELD records

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