Commercial Driver's License (General Knowledge)

Specialized & Licensing - Commercial Driver's License (General Knowledge) (part of DMV & Licensing)

Practical Applications

Daily Pre-Trip Inspection Routine

Alright, let's turn theory into action! The daily pre-trip inspection isn't just a checklist; it's a routine, a habit that keeps you safe and on schedule. Doing it right, every single time, is one of the most important practical skills you'll master as a commercial driver. Think of it as your vehicle's morning check-up!

Before You Even Touch the Truck

  1. Review Last DVIR: Check the previous driver's inspection report (DVIR) for any defects. Make sure they've been signed off as repaired or if you can legally drive with them.
  2. Gather Gear: Have your gloves, flashlight (even in daylight!), tire thumper, and anything else you might need.
  3. Check Surrounding Area: Look under and around the vehicle for fresh leaks, fallen parts, or anything unusual. Are there chocks on the wheels if parked on a slope?

Inside the Cab (Starting the Engine)

  1. Get In & Secure: Enter the cab, put on your seatbelt, and adjust your seat and mirrors.
  2. Basic Controls: Test your horn, wipers, washers, and lights (low beam, high beam, turn signals). Check the heater/defroster.
  3. Gauges & Indicators: Turn the key to the "on" position (without starting). Look for warning lights (ABS, low air, check engine). They should light up and then go out.
  4. Air Brake Tests: This is a big one, as we discussed in the "Air Brakes Explained" topic.
    • Leakage Tests: Static and Applied.
    • Low Air Warning: Pump brakes until warning comes on.
    • Spring Brake Pop-Out: Continue pumping until parking brake knob pops out.
    • Governor Test: Start engine, build air to cut-out, then pump down to cut-in.
  5. Steering Wheel Play: With the engine running, check for excessive play (more than about 10 degrees or 2 inches on a 20-inch wheel) in the steering wheel.
  6. Hydraulic Brake Test (if applicable): Pump pedal three times, then hold for five seconds. Pedal should not move.

The Walk-Around (Systematic Approach)

This is where most of the inspection happens. Pick a starting point (e.g., driver's side front) and work your way around the vehicle systematically, section by section.

  • Front of Vehicle:
    • Lights (clean, working, correct color)
    • Windshield (clean, no cracks)
    • Mirrors (clean, adjusted, not broken)
  • Engine Compartment (Under Hood):
    • Fluid levels (oil, coolant, power steering, washer fluid)
    • Hoses & Belts (no leaks, cracks, frays)
    • Wiring (secured, not frayed)
    • Steering linkage (no loose joints, bent rods)
  • Front Wheels & Suspension:
    • Tires (condition, tread depth, proper inflation - use a gauge!)
    • Rims (no bends, cracks)
    • Lug Nuts (all present, no signs of looseness)
    • Hub Seals (no leaks)
    • Springs, Shocks, U-bolts (not broken or cracked)
    • Brakes (air chambers, hoses, slack adjusters - check for proper adjustment)
  • Sides of Vehicle & Fuel Tank:
    • Body damage
    • Fuel tank (secure, no leaks)
    • Battery box (secure, no corrosion)
  • Rear of Tractor / Coupling System:
    • Fifth wheel (properly greased, no cracks, kingpin locked)
    • Air/Electrical lines (no chafing, secure)
  • Trailer (if applicable): Repeat wheel, tire, brake, and suspension checks.
    • Landing gear (fully raised/lowered as needed, no damage)
    • Lights & Reflectors (all working, clean)
    • Cargo securement (straps, chains, load bars - tight and secure)
    • Splash guards/mud flaps (present, not damaged)
  • Rear of Vehicle:
    • All rear lights (brake, turn, tail, clearance)
    • License plate (clean, visible)
    • Bumpers (secure)

Final Check & Reporting

  • Re-check anything suspicious.
  • Complete DVIR: Document any defects found, even minor ones. Sign it. If a defect makes the vehicle unsafe, it cannot be driven until repaired. By following this routine, you're not just passing a test; you're building a habit that will make you a professional, safe driver for years to come.

Examples

  • Before starting your engine, you check the previous day's DVIR and confirm that a reported faulty headlight was fixed and signed off by a mechanic.

  • During your walk-around, you use your tire thumper to check all tires, noticing that one inner dual tire sounds flat, prompting you to inflate it before departure.

  • You test your air brakes in the cab, ensuring the low air warning light activates around 60 psi and the parking brake knob pops out between 20-45 psi, confirming system functionality.

In a Nutshell

A thorough daily pre-trip inspection is a critical routine for CDL drivers. It involves reviewing previous DVIRs, checking cab controls and air brake systems (leakage, warning, pop-out, governor), and performing a systematic walk-around of the entire vehicle (tires, lights, fluids, suspension, coupling, cargo securement). All defects must be documented on a DVIR.