Maine CDL General Knowledge cheat sheet

Pre-trip inspection must cover three areas: engine compartment, cab and controls, and the exterior walk-around (front, sides, rear, lights, couplings).

CDL pre-trip inspection is a pass/fail skill: missing a defect that would cause a breakdown or crash fails the test; the candidate must verbally name each part and its condition.

Engine compartment checks: engine oil level, coolant level, power steering fluid, windshield washer fluid, belts (fraying, snugness, cracks), hoses (leaks, cracks), and battery securement.

Steering system check: steering box not cracked or leaking, hoses secure, tie rod and drag link straight and free of cracks, castle nuts and cotter pins in place, no excessive play.

Brake checks: slack adjusters (manual adjust type should move less than one inch by hand at the push rod), brake chambers and hoses (no cracks, cuts, leaks), drums or rotors free of cracks and oil.

Tire checks: tread depth of at least 4/32 inch on front tires and 2/32 inch on all other tires, adequate inflation, no recaps on front wheels, no deep cuts or bulges.

Lighting check: headlights (high and low), clearance and marker lights, turn signals, four-way flashers, brake lights, tail lights, and reflective tape all clean and working.

Leak check: after the engine is running and the system is charged, build full air pressure, shut off the engine, and verify pressure does not drop more than 3 psi in one minute (single vehicle) with brakes released.

Inspection report: the driver must review the last vehicle inspection report, sign it if defects are noted, and certify that required repairs were performed before driving.

Total stopping distance = perception distance + reaction distance + brake lag distance + braking distance; at 55 mph this totals roughly 419 feet for a loaded tractor-trailer on dry pavement.

Perception distance at 55 mph is about 60 feet; reaction distance is about 61 feet; brake lag for air brakes adds about 32 feet before braking begins.

The three-step approach to a hazard: recognize the hazard, understand the defense, and act correctly in time.

Backing: use a helper whenever possible, back toward the driver's side (left) when practical, and stop immediately if you lose sight of the helper.

A vehicle's blind spots (No-Zones) extend roughly 20 feet in front, 30 feet behind, and one lane on each side; the right side blind spot is the largest.

Speed and curves: reduce speed before entering a curve, maintain steady speed through it, and accelerate gently after the rear of the vehicle has cleared the curve to avoid off-tracking.

Off-tracking: the rear wheels follow a shorter path than the front wheels; a tractor-trailer can off-track by as much as one lane width in a tight turn.

Parking on a hill: with a manual transmission, turn the front wheels toward the curb when facing downhill, away from the curb when facing uphill, and set the parking brake.

For a manual transmission, double-clutch: press the clutch, shift to neutral, release the clutch, press the clutch again, and shift into the next gear while matching engine speed.

Upshift pattern typically goes 1-2-3-4-5 (low to high); downshift in reverse order and never skip gears unless you are sure of the road speed and engine rpm.

RPM ranges: upshift around 1,200-1,500 rpm for a loaded heavy truck; downshift before rpm drops below the engine's governed low limit to avoid lugging.

Never coast with the clutch depressed or in neutral: you lose engine braking and the ability to accelerate out of a hazard.

On a downgrade, select a gear low enough that engine braking holds the vehicle's speed without using the service brakes continuously; do not ride the brakes.

Automatic transmissions: use the selector in the Drive position for normal driving; use a lower range (e.g., 2 or 3) for long downgrades to engage engine braking.

If you miss a gear on a grade, stop, set the parking brake, and start over in the lowest gear rather than forcing the shift.

Shifting on ice or snow: shift smoothly and early; abrupt downshifts can break traction on the drive wheels.

Signal at least 100 feet before turning in a business or residential area; the same distance applies to lane changes and stops in most states.

Signal continuously for at least the last 100 feet before a turn; cancel the signal after completing the maneuver.

Use four-way flashers when stopped on the shoulder, when moving slowly (below 40 mph) on a highway, or when your vehicle is a hazard to others.

Mirror use: check mirrors every 5-8 seconds and before any lane change, turn, or stop; adjust mirrors so you see a small part of your own vehicle.

At night, dim high beams within 500 feet of an oncoming vehicle and within 200 feet when following another vehicle.

Use the horn only to warn others of danger; a light tap is appropriate to alert a driver drifting into your lane.

Eye lead time: look at least 12-15 seconds ahead in city driving and 20-25 seconds on the highway to spot hazards early.

Communicate with turn signals, brake lights, four-way flashers, headlights, horn, and lane position; do not rely on hand signals at night or in poor visibility.

Following distance rule: one second for each 10 feet of vehicle length at speeds below 40 mph; add one second for speeds above 40 mph. A 60-foot vehicle at 40 mph needs 6 seconds.

At 55 mph a 60-foot vehicle needs at least 7 seconds of following distance on dry pavement; add more in rain, fog, or darkness.

Lane position: keep the vehicle centered in the lane; on a two-lane road, stay slightly right of center to increase clearance from oncoming traffic.

Space to the sides: avoid driving beside another vehicle; maintain at least one lane of space on each side when possible, and more on the right where the blind spot is largest.

Space ahead: maintain a following distance that allows you to stop within the distance you can see to be clear; never overdrive your headlights.

Space behind: if a tailgater is close, increase your own following distance ahead so you can brake gradually, and change lanes to let them pass.

Space to pass: before passing, ensure you have enough clear road ahead to complete the pass and return to your lane; a heavy vehicle needs more distance to accelerate.

Backing and parking: use a spotter, get out and look if unsure, and leave enough space to pull out without striking nearby objects.

Hazard types: stationary (parked cars, construction), moving (other vehicles, pedestrians), and environmental (weather, road surface).

The Smith System five keys: aim high in steering, get the big picture, keep your eyes moving, leave yourself an out, and make sure they see you.

Brake failure: pump the brakes (if air pressure is present), downshift, use the parking brake gradually, and look for an escape route such as a runaway truck ramp.

Tire blowout: hold the steering wheel firmly, keep the vehicle straight, ease off the accelerator, and brake gently once the vehicle is under control.

Skid recovery: steer in the direction you want the front of the vehicle to go, ease off the accelerator, and avoid hard braking until the tires regain traction.

Hydroplaning: occurs when tires ride on a film of water; ease off the accelerator, do not brake hard, and steer straight until traction returns.

Fire: stop, shut off the engine, get passengers out and away, and use a fire extinguisher only on a small fire; never open the hood fully if the engine is burning.

Runaway truck ramp: use it if you lose braking on a downgrade; steer straight into the ramp and do not brake hard on the gravel.

Night driving: reduce speed so you can stop within the distance illuminated by your headlights; low beams show about 160 feet, high beams about 350 feet.

Dim high beams within 500 feet of an oncoming vehicle and within 200 feet when following; use low beams in fog, rain, and snow to reduce glare.

Fog: slow down, use low beams and fog lights, increase following distance, and be ready to stop; do not use high beams because they reflect off the fog.

Rain: reduce speed, increase following distance, and be alert for hydroplaning; wet roads can double stopping distance.

Snow and ice: reduce speed, brake gently and early, avoid abrupt steering, and use engine braking on downgrades; chains may be required in mountain passes.

High winds: reduce speed, grip the wheel firmly, watch for wind gusts when passing buildings or bridges, and be alert to blown-over vehicles.

Extreme heat: watch tire pressure and engine temperature; hot pavement can cause tire failure, and engine overheating may require stopping to cool.

Winter pre-trip: check antifreeze, battery, wipers, defroster, tire chains, and emergency supplies; carry a flashlight, blanket, and food/water.

Cargo must be secured so it cannot shift, spill, or fall; use tiedowns with a working load limit at least 50% of the cargo weight for each tie-down.

Minimum tiedowns: one for cargo up to 5 feet and 1,100 pounds; two for cargo over 5 feet but under 10 feet or over 1,100 pounds; three for cargo 10 feet or longer.

Aggregate working load limit of all tiedowns must be at least 50% of the cargo weight; use a minimum of one tiedown every 10 feet of cargo length.

Front-end structure: cargo must not obscure the driver's view, and the vehicle must have a front-end structure or cab guard if cargo could shift forward.

Cargo height: maximum height is generally 13 feet 6 inches in most states (14 feet in some western states); check the route for low bridges.

Cargo width: maximum width is 8 feet 6 inches on most highways; oversize loads require permits and may need pilot cars.

Cargo weight: do not exceed axle weight ratings, tire load limits, or the vehicle's gross vehicle weight rating (GVWR); weigh the load at a scale.

Securement inspection: check tiedowns and cargo at the start of the trip, after the first 50 miles, every 150 miles or 3 hours thereafter, and after any emergency stop.

Pre-trip: inspect the bus exterior and interior, test lights, brakes, steering, and emergency exits, and check that the aisle and emergency exits are clear.

Passenger safety briefing: explain seat belt use, emergency exits, and the location of the fire extinguisher and first aid kit before departure.

Standee rule: do not allow passengers to stand forward of the standee line or in the aisle while the bus is moving.

Loading and unloading: stop close to the curb, set the parking brake, and use the door controls; watch for passengers who may fall or be struck by traffic.

Emergency evacuation: stop the bus, set the parking brake, shut off the engine, open the exits, and lead passengers to a safe location away from traffic.

Railroad crossings: stop at all crossings (except where exempt), turn off noisy equipment, open the door or window to listen, and cross only when clear.

Passenger comfort and safety: avoid sudden stops and starts, and be alert to passengers who are elderly or have disabilities; secure wheelchairs with four tiedowns.

Alcohol and drugs: passengers may not consume alcohol on the bus; the driver must not operate a commercial vehicle with a blood alcohol concentration of 0.04 or higher.

Air brake system components: compressor, governor, air tanks (wet, primary, secondary), safety valve, brake chambers, slack adjusters, and the low pressure warning device.

The governor cuts the compressor in at about 100 psi and out at about 125 psi; the safety valve releases at about 150 psi.

Low pressure warning: must activate before pressure drops below 60 psi; the spring brakes will apply when pressure drops to about 20-45 psi.

Static leak test: with the engine off and the system charged, pressure should not drop more than 3 psi in one minute for a single vehicle or 4 psi for a combination vehicle.

Applied leak test: with the brakes fully applied, pressure should not drop more than 4 psi in one minute for a single vehicle or 6 psi for a combination vehicle.

Tractor protection valve test: with the trailer supply line disconnected, the trailer spring brakes should apply and the tractor protection valve should close, preventing air loss.

Slack adjuster check: with the brakes released, the push rod should move no more than 1 inch by hand; with the brakes applied, the push rod angle should be about 90 degrees.

Brake lag: air brakes take about 0.4-0.6 seconds to apply, so stopping distance is longer than with hydraulic brakes; allow extra following distance.

Fifth wheel and kingpin: check that the fifth wheel jaws are locked around the kingpin, the release lever is secured, and the fifth wheel is greased.

Trailer air lines: connect the emergency (supply) line first, then the service line; check that the lines are not crossed or kinked.

Tug test: after coupling, pull forward gently with the trailer brakes locked to confirm the kingpin is locked in the fifth wheel.

Landing gear: fully raised after coupling, with the crank handle secured; the landing gear must not touch the ground while driving.

Trailer brake check: with the tractor brakes released and the trailer brakes applied, the combination should not move; test the trailer spring brakes with the supply line disconnected.

Off-tracking and rearward amplification: the rear trailer of a double or triple swings wider on turns; watch for this when turning or changing lanes.

Jackknife prevention: brake gently on slippery surfaces, avoid abrupt steering, and keep the tractor and trailer aligned; a jackknife occurs when the trailer pushes the tractor sideways.

Swing radius: a combination vehicle's rear wheels cut the corner, so swing wide before turning and watch the trailer's rear in the mirrors.

Hours of service: 11 hours driving after 10 consecutive hours off duty; 14-hour on-duty window; 30-minute break after 8 hours of driving; 60/70-hour limit in 7/8 days.

ELD rule: most interstate drivers must use an electronic logging device to record hours of service; paper logs are allowed only in limited exceptions.

CDL medical card: drivers must carry a current DOT medical examiner's certificate and meet the physical qualification standards.

Drug and alcohol testing: pre-employment, random, post-accident, reasonable suspicion, return-to-duty, and follow-up testing are required; BAC limit is 0.04.

Vehicle inspection report: drivers must review and sign the previous report and certify repairs before operating; keep the report for at least 90 days.

Emergency equipment: fire extinguisher (minimum 5 BC rating), three reflective triangles, and spare fuses are required on most commercial vehicles.

Load securement and weight: obey posted weight limits, bridge formulas, and state permits; overweight vehicles are subject to fines and out-of-service orders.

Incident reporting: report any accident involving injury, death, or disabling damage to the motor carrier immediately; a written report is required within 24 hours in many cases.

Pre-trip inspection must cover three areas: engine compartment, cab and controls, and the exterior walk-around (front, sides, rear, lights, couplings).

CDL pre-trip inspection is a pass/fail skill: missing a defect that would cause a breakdown or crash fails the test; the candidate must verbally name each part and its condition.

Engine compartment checks: engine oil level, coolant level, power steering fluid, windshield washer fluid, belts (fraying, snugness, cracks), hoses (leaks, cracks), and battery securement.

Steering system check: steering box not cracked or leaking, hoses secure, tie rod and drag link straight and free of cracks, castle nuts and cotter pins in place, no excessive play.

Brake checks: slack adjusters (manual adjust type should move less than one inch by hand at the push rod), brake chambers and hoses (no cracks, cuts, leaks), drums or rotors free of cracks and oil.

Tire checks: tread depth of at least 4/32 inch on front tires and 2/32 inch on all other tires, adequate inflation, no recaps on front wheels, no deep cuts or bulges.

Lighting check: headlights (high and low), clearance and marker lights, turn signals, four-way flashers, brake lights, tail lights, and reflective tape all clean and working.

Leak check: after the engine is running and the system is charged, build full air pressure, shut off the engine, and verify pressure does not drop more than 3 psi in one minute (single vehicle) with brakes released.

Inspection report: the driver must review the last vehicle inspection report, sign it if defects are noted, and certify that required repairs were performed before driving.

Total stopping distance = perception distance + reaction distance + brake lag distance + braking distance; at 55 mph this totals roughly 419 feet for a loaded tractor-trailer on dry pavement.

Perception distance at 55 mph is about 60 feet; reaction distance is about 61 feet; brake lag for air brakes adds about 32 feet before braking begins.

The three-step approach to a hazard: recognize the hazard, understand the defense, and act correctly in time.

Backing: use a helper whenever possible, back toward the driver's side (left) when practical, and stop immediately if you lose sight of the helper.

A vehicle's blind spots (No-Zones) extend roughly 20 feet in front, 30 feet behind, and one lane on each side; the right side blind spot is the largest.

Speed and curves: reduce speed before entering a curve, maintain steady speed through it, and accelerate gently after the rear of the vehicle has cleared the curve to avoid off-tracking.

Off-tracking: the rear wheels follow a shorter path than the front wheels; a tractor-trailer can off-track by as much as one lane width in a tight turn.

Parking on a hill: with a manual transmission, turn the front wheels toward the curb when facing downhill, away from the curb when facing uphill, and set the parking brake.

For a manual transmission, double-clutch: press the clutch, shift to neutral, release the clutch, press the clutch again, and shift into the next gear while matching engine speed.

Upshift pattern typically goes 1-2-3-4-5 (low to high); downshift in reverse order and never skip gears unless you are sure of the road speed and engine rpm.

RPM ranges: upshift around 1,200-1,500 rpm for a loaded heavy truck; downshift before rpm drops below the engine's governed low limit to avoid lugging.

Never coast with the clutch depressed or in neutral: you lose engine braking and the ability to accelerate out of a hazard.

On a downgrade, select a gear low enough that engine braking holds the vehicle's speed without using the service brakes continuously; do not ride the brakes.

Automatic transmissions: use the selector in the Drive position for normal driving; use a lower range (e.g., 2 or 3) for long downgrades to engage engine braking.

If you miss a gear on a grade, stop, set the parking brake, and start over in the lowest gear rather than forcing the shift.

Shifting on ice or snow: shift smoothly and early; abrupt downshifts can break traction on the drive wheels.

Signal at least 100 feet before turning in a business or residential area; the same distance applies to lane changes and stops in most states.

Signal continuously for at least the last 100 feet before a turn; cancel the signal after completing the maneuver.

Use four-way flashers when stopped on the shoulder, when moving slowly (below 40 mph) on a highway, or when your vehicle is a hazard to others.

Mirror use: check mirrors every 5-8 seconds and before any lane change, turn, or stop; adjust mirrors so you see a small part of your own vehicle.

At night, dim high beams within 500 feet of an oncoming vehicle and within 200 feet when following another vehicle.

Use the horn only to warn others of danger; a light tap is appropriate to alert a driver drifting into your lane.

Eye lead time: look at least 12-15 seconds ahead in city driving and 20-25 seconds on the highway to spot hazards early.

Communicate with turn signals, brake lights, four-way flashers, headlights, horn, and lane position; do not rely on hand signals at night or in poor visibility.

Following distance rule: one second for each 10 feet of vehicle length at speeds below 40 mph; add one second for speeds above 40 mph. A 60-foot vehicle at 40 mph needs 6 seconds.

At 55 mph a 60-foot vehicle needs at least 7 seconds of following distance on dry pavement; add more in rain, fog, or darkness.

Lane position: keep the vehicle centered in the lane; on a two-lane road, stay slightly right of center to increase clearance from oncoming traffic.

Space to the sides: avoid driving beside another vehicle; maintain at least one lane of space on each side when possible, and more on the right where the blind spot is largest.

Space ahead: maintain a following distance that allows you to stop within the distance you can see to be clear; never overdrive your headlights.

Space behind: if a tailgater is close, increase your own following distance ahead so you can brake gradually, and change lanes to let them pass.

Space to pass: before passing, ensure you have enough clear road ahead to complete the pass and return to your lane; a heavy vehicle needs more distance to accelerate.

Backing and parking: use a spotter, get out and look if unsure, and leave enough space to pull out without striking nearby objects.

Hazard types: stationary (parked cars, construction), moving (other vehicles, pedestrians), and environmental (weather, road surface).

The Smith System five keys: aim high in steering, get the big picture, keep your eyes moving, leave yourself an out, and make sure they see you.

Brake failure: pump the brakes (if air pressure is present), downshift, use the parking brake gradually, and look for an escape route such as a runaway truck ramp.

Tire blowout: hold the steering wheel firmly, keep the vehicle straight, ease off the accelerator, and brake gently once the vehicle is under control.

Skid recovery: steer in the direction you want the front of the vehicle to go, ease off the accelerator, and avoid hard braking until the tires regain traction.

Hydroplaning: occurs when tires ride on a film of water; ease off the accelerator, do not brake hard, and steer straight until traction returns.

Fire: stop, shut off the engine, get passengers out and away, and use a fire extinguisher only on a small fire; never open the hood fully if the engine is burning.

Runaway truck ramp: use it if you lose braking on a downgrade; steer straight into the ramp and do not brake hard on the gravel.

Night driving: reduce speed so you can stop within the distance illuminated by your headlights; low beams show about 160 feet, high beams about 350 feet.

Dim high beams within 500 feet of an oncoming vehicle and within 200 feet when following; use low beams in fog, rain, and snow to reduce glare.

Fog: slow down, use low beams and fog lights, increase following distance, and be ready to stop; do not use high beams because they reflect off the fog.

Rain: reduce speed, increase following distance, and be alert for hydroplaning; wet roads can double stopping distance.

Snow and ice: reduce speed, brake gently and early, avoid abrupt steering, and use engine braking on downgrades; chains may be required in mountain passes.

High winds: reduce speed, grip the wheel firmly, watch for wind gusts when passing buildings or bridges, and be alert to blown-over vehicles.

Extreme heat: watch tire pressure and engine temperature; hot pavement can cause tire failure, and engine overheating may require stopping to cool.

Winter pre-trip: check antifreeze, battery, wipers, defroster, tire chains, and emergency supplies; carry a flashlight, blanket, and food/water.

Cargo must be secured so it cannot shift, spill, or fall; use tiedowns with a working load limit at least 50% of the cargo weight for each tie-down.

Minimum tiedowns: one for cargo up to 5 feet and 1,100 pounds; two for cargo over 5 feet but under 10 feet or over 1,100 pounds; three for cargo 10 feet or longer.

Aggregate working load limit of all tiedowns must be at least 50% of the cargo weight; use a minimum of one tiedown every 10 feet of cargo length.

Front-end structure: cargo must not obscure the driver's view, and the vehicle must have a front-end structure or cab guard if cargo could shift forward.

Cargo height: maximum height is generally 13 feet 6 inches in most states (14 feet in some western states); check the route for low bridges.

Cargo width: maximum width is 8 feet 6 inches on most highways; oversize loads require permits and may need pilot cars.

Cargo weight: do not exceed axle weight ratings, tire load limits, or the vehicle's gross vehicle weight rating (GVWR); weigh the load at a scale.

Securement inspection: check tiedowns and cargo at the start of the trip, after the first 50 miles, every 150 miles or 3 hours thereafter, and after any emergency stop.

Pre-trip: inspect the bus exterior and interior, test lights, brakes, steering, and emergency exits, and check that the aisle and emergency exits are clear.

Passenger safety briefing: explain seat belt use, emergency exits, and the location of the fire extinguisher and first aid kit before departure.

Standee rule: do not allow passengers to stand forward of the standee line or in the aisle while the bus is moving.

Loading and unloading: stop close to the curb, set the parking brake, and use the door controls; watch for passengers who may fall or be struck by traffic.

Emergency evacuation: stop the bus, set the parking brake, shut off the engine, open the exits, and lead passengers to a safe location away from traffic.

Railroad crossings: stop at all crossings (except where exempt), turn off noisy equipment, open the door or window to listen, and cross only when clear.

Passenger comfort and safety: avoid sudden stops and starts, and be alert to passengers who are elderly or have disabilities; secure wheelchairs with four tiedowns.

Alcohol and drugs: passengers may not consume alcohol on the bus; the driver must not operate a commercial vehicle with a blood alcohol concentration of 0.04 or higher.

Air brake system components: compressor, governor, air tanks (wet, primary, secondary), safety valve, brake chambers, slack adjusters, and the low pressure warning device.

The governor cuts the compressor in at about 100 psi and out at about 125 psi; the safety valve releases at about 150 psi.

Low pressure warning: must activate before pressure drops below 60 psi; the spring brakes will apply when pressure drops to about 20-45 psi.

Static leak test: with the engine off and the system charged, pressure should not drop more than 3 psi in one minute for a single vehicle or 4 psi for a combination vehicle.

Applied leak test: with the brakes fully applied, pressure should not drop more than 4 psi in one minute for a single vehicle or 6 psi for a combination vehicle.

Tractor protection valve test: with the trailer supply line disconnected, the trailer spring brakes should apply and the tractor protection valve should close, preventing air loss.

Slack adjuster check: with the brakes released, the push rod should move no more than 1 inch by hand; with the brakes applied, the push rod angle should be about 90 degrees.

Brake lag: air brakes take about 0.4-0.6 seconds to apply, so stopping distance is longer than with hydraulic brakes; allow extra following distance.

Fifth wheel and kingpin: check that the fifth wheel jaws are locked around the kingpin, the release lever is secured, and the fifth wheel is greased.

Trailer air lines: connect the emergency (supply) line first, then the service line; check that the lines are not crossed or kinked.

Tug test: after coupling, pull forward gently with the trailer brakes locked to confirm the kingpin is locked in the fifth wheel.

Landing gear: fully raised after coupling, with the crank handle secured; the landing gear must not touch the ground while driving.

Trailer brake check: with the tractor brakes released and the trailer brakes applied, the combination should not move; test the trailer spring brakes with the supply line disconnected.

Off-tracking and rearward amplification: the rear trailer of a double or triple swings wider on turns; watch for this when turning or changing lanes.

Jackknife prevention: brake gently on slippery surfaces, avoid abrupt steering, and keep the tractor and trailer aligned; a jackknife occurs when the trailer pushes the tractor sideways.

Swing radius: a combination vehicle's rear wheels cut the corner, so swing wide before turning and watch the trailer's rear in the mirrors.

Hours of service: 11 hours driving after 10 consecutive hours off duty; 14-hour on-duty window; 30-minute break after 8 hours of driving; 60/70-hour limit in 7/8 days.

ELD rule: most interstate drivers must use an electronic logging device to record hours of service; paper logs are allowed only in limited exceptions.

CDL medical card: drivers must carry a current DOT medical examiner's certificate and meet the physical qualification standards.

Drug and alcohol testing: pre-employment, random, post-accident, reasonable suspicion, return-to-duty, and follow-up testing are required; BAC limit is 0.04.

Vehicle inspection report: drivers must review and sign the previous report and certify repairs before operating; keep the report for at least 90 days.

Emergency equipment: fire extinguisher (minimum 5 BC rating), three reflective triangles, and spare fuses are required on most commercial vehicles.

Load securement and weight: obey posted weight limits, bridge formulas, and state permits; overweight vehicles are subject to fines and out-of-service orders.

Incident reporting: report any accident involving injury, death, or disabling damage to the motor carrier immediately; a written report is required within 24 hours in many cases.

Pre-trip inspection must cover three areas: engine compartment, cab and controls, and the exterior walk-around (front, sides, rear, lights, couplings).

CDL pre-trip inspection is a pass/fail skill: missing a defect that would cause a breakdown or crash fails the test; the candidate must verbally name each part and its condition.

Engine compartment checks: engine oil level, coolant level, power steering fluid, windshield washer fluid, belts (fraying, snugness, cracks), hoses (leaks, cracks), and battery securement.

Steering system check: steering box not cracked or leaking, hoses secure, tie rod and drag link straight and free of cracks, castle nuts and cotter pins in place, no excessive play.

Brake checks: slack adjusters (manual adjust type should move less than one inch by hand at the push rod), brake chambers and hoses (no cracks, cuts, leaks), drums or rotors free of cracks and oil.

Tire checks: tread depth of at least 4/32 inch on front tires and 2/32 inch on all other tires, adequate inflation, no recaps on front wheels, no deep cuts or bulges.

Lighting check: headlights (high and low), clearance and marker lights, turn signals, four-way flashers, brake lights, tail lights, and reflective tape all clean and working.

Leak check: after the engine is running and the system is charged, build full air pressure, shut off the engine, and verify pressure does not drop more than 3 psi in one minute (single vehicle) with brakes released.

Inspection report: the driver must review the last vehicle inspection report, sign it if defects are noted, and certify that required repairs were performed before driving.

Total stopping distance = perception distance + reaction distance + brake lag distance + braking distance; at 55 mph this totals roughly 419 feet for a loaded tractor-trailer on dry pavement.

Perception distance at 55 mph is about 60 feet; reaction distance is about 61 feet; brake lag for air brakes adds about 32 feet before braking begins.

The three-step approach to a hazard: recognize the hazard, understand the defense, and act correctly in time.

Backing: use a helper whenever possible, back toward the driver's side (left) when practical, and stop immediately if you lose sight of the helper.

A vehicle's blind spots (No-Zones) extend roughly 20 feet in front, 30 feet behind, and one lane on each side; the right side blind spot is the largest.

Speed and curves: reduce speed before entering a curve, maintain steady speed through it, and accelerate gently after the rear of the vehicle has cleared the curve to avoid off-tracking.

Off-tracking: the rear wheels follow a shorter path than the front wheels; a tractor-trailer can off-track by as much as one lane width in a tight turn.

Parking on a hill: with a manual transmission, turn the front wheels toward the curb when facing downhill, away from the curb when facing uphill, and set the parking brake.

For a manual transmission, double-clutch: press the clutch, shift to neutral, release the clutch, press the clutch again, and shift into the next gear while matching engine speed.

Upshift pattern typically goes 1-2-3-4-5 (low to high); downshift in reverse order and never skip gears unless you are sure of the road speed and engine rpm.

RPM ranges: upshift around 1,200-1,500 rpm for a loaded heavy truck; downshift before rpm drops below the engine's governed low limit to avoid lugging.

Never coast with the clutch depressed or in neutral: you lose engine braking and the ability to accelerate out of a hazard.

On a downgrade, select a gear low enough that engine braking holds the vehicle's speed without using the service brakes continuously; do not ride the brakes.

Automatic transmissions: use the selector in the Drive position for normal driving; use a lower range (e.g., 2 or 3) for long downgrades to engage engine braking.

If you miss a gear on a grade, stop, set the parking brake, and start over in the lowest gear rather than forcing the shift.

Shifting on ice or snow: shift smoothly and early; abrupt downshifts can break traction on the drive wheels.

Signal at least 100 feet before turning in a business or residential area; the same distance applies to lane changes and stops in most states.

Signal continuously for at least the last 100 feet before a turn; cancel the signal after completing the maneuver.

Use four-way flashers when stopped on the shoulder, when moving slowly (below 40 mph) on a highway, or when your vehicle is a hazard to others.

Mirror use: check mirrors every 5-8 seconds and before any lane change, turn, or stop; adjust mirrors so you see a small part of your own vehicle.

At night, dim high beams within 500 feet of an oncoming vehicle and within 200 feet when following another vehicle.

Use the horn only to warn others of danger; a light tap is appropriate to alert a driver drifting into your lane.

Eye lead time: look at least 12-15 seconds ahead in city driving and 20-25 seconds on the highway to spot hazards early.

Communicate with turn signals, brake lights, four-way flashers, headlights, horn, and lane position; do not rely on hand signals at night or in poor visibility.

Following distance rule: one second for each 10 feet of vehicle length at speeds below 40 mph; add one second for speeds above 40 mph. A 60-foot vehicle at 40 mph needs 6 seconds.

At 55 mph a 60-foot vehicle needs at least 7 seconds of following distance on dry pavement; add more in rain, fog, or darkness.

Lane position: keep the vehicle centered in the lane; on a two-lane road, stay slightly right of center to increase clearance from oncoming traffic.

Space to the sides: avoid driving beside another vehicle; maintain at least one lane of space on each side when possible, and more on the right where the blind spot is largest.

Space ahead: maintain a following distance that allows you to stop within the distance you can see to be clear; never overdrive your headlights.

Space behind: if a tailgater is close, increase your own following distance ahead so you can brake gradually, and change lanes to let them pass.

Space to pass: before passing, ensure you have enough clear road ahead to complete the pass and return to your lane; a heavy vehicle needs more distance to accelerate.

Backing and parking: use a spotter, get out and look if unsure, and leave enough space to pull out without striking nearby objects.

Hazard types: stationary (parked cars, construction), moving (other vehicles, pedestrians), and environmental (weather, road surface).

The Smith System five keys: aim high in steering, get the big picture, keep your eyes moving, leave yourself an out, and make sure they see you.

Brake failure: pump the brakes (if air pressure is present), downshift, use the parking brake gradually, and look for an escape route such as a runaway truck ramp.

Tire blowout: hold the steering wheel firmly, keep the vehicle straight, ease off the accelerator, and brake gently once the vehicle is under control.

Skid recovery: steer in the direction you want the front of the vehicle to go, ease off the accelerator, and avoid hard braking until the tires regain traction.

Hydroplaning: occurs when tires ride on a film of water; ease off the accelerator, do not brake hard, and steer straight until traction returns.

Fire: stop, shut off the engine, get passengers out and away, and use a fire extinguisher only on a small fire; never open the hood fully if the engine is burning.

Runaway truck ramp: use it if you lose braking on a downgrade; steer straight into the ramp and do not brake hard on the gravel.

Night driving: reduce speed so you can stop within the distance illuminated by your headlights; low beams show about 160 feet, high beams about 350 feet.

Dim high beams within 500 feet of an oncoming vehicle and within 200 feet when following; use low beams in fog, rain, and snow to reduce glare.

Fog: slow down, use low beams and fog lights, increase following distance, and be ready to stop; do not use high beams because they reflect off the fog.

Rain: reduce speed, increase following distance, and be alert for hydroplaning; wet roads can double stopping distance.

Snow and ice: reduce speed, brake gently and early, avoid abrupt steering, and use engine braking on downgrades; chains may be required in mountain passes.

High winds: reduce speed, grip the wheel firmly, watch for wind gusts when passing buildings or bridges, and be alert to blown-over vehicles.

Extreme heat: watch tire pressure and engine temperature; hot pavement can cause tire failure, and engine overheating may require stopping to cool.

Winter pre-trip: check antifreeze, battery, wipers, defroster, tire chains, and emergency supplies; carry a flashlight, blanket, and food/water.

Cargo must be secured so it cannot shift, spill, or fall; use tiedowns with a working load limit at least 50% of the cargo weight for each tie-down.

Minimum tiedowns: one for cargo up to 5 feet and 1,100 pounds; two for cargo over 5 feet but under 10 feet or over 1,100 pounds; three for cargo 10 feet or longer.

Aggregate working load limit of all tiedowns must be at least 50% of the cargo weight; use a minimum of one tiedown every 10 feet of cargo length.

Front-end structure: cargo must not obscure the driver's view, and the vehicle must have a front-end structure or cab guard if cargo could shift forward.

Cargo height: maximum height is generally 13 feet 6 inches in most states (14 feet in some western states); check the route for low bridges.

Cargo width: maximum width is 8 feet 6 inches on most highways; oversize loads require permits and may need pilot cars.

Cargo weight: do not exceed axle weight ratings, tire load limits, or the vehicle's gross vehicle weight rating (GVWR); weigh the load at a scale.

Securement inspection: check tiedowns and cargo at the start of the trip, after the first 50 miles, every 150 miles or 3 hours thereafter, and after any emergency stop.

Pre-trip: inspect the bus exterior and interior, test lights, brakes, steering, and emergency exits, and check that the aisle and emergency exits are clear.

Passenger safety briefing: explain seat belt use, emergency exits, and the location of the fire extinguisher and first aid kit before departure.

Standee rule: do not allow passengers to stand forward of the standee line or in the aisle while the bus is moving.

Loading and unloading: stop close to the curb, set the parking brake, and use the door controls; watch for passengers who may fall or be struck by traffic.

Emergency evacuation: stop the bus, set the parking brake, shut off the engine, open the exits, and lead passengers to a safe location away from traffic.

Railroad crossings: stop at all crossings (except where exempt), turn off noisy equipment, open the door or window to listen, and cross only when clear.

Passenger comfort and safety: avoid sudden stops and starts, and be alert to passengers who are elderly or have disabilities; secure wheelchairs with four tiedowns.

Alcohol and drugs: passengers may not consume alcohol on the bus; the driver must not operate a commercial vehicle with a blood alcohol concentration of 0.04 or higher.

Air brake system components: compressor, governor, air tanks (wet, primary, secondary), safety valve, brake chambers, slack adjusters, and the low pressure warning device.

The governor cuts the compressor in at about 100 psi and out at about 125 psi; the safety valve releases at about 150 psi.

Low pressure warning: must activate before pressure drops below 60 psi; the spring brakes will apply when pressure drops to about 20-45 psi.

Static leak test: with the engine off and the system charged, pressure should not drop more than 3 psi in one minute for a single vehicle or 4 psi for a combination vehicle.

Applied leak test: with the brakes fully applied, pressure should not drop more than 4 psi in one minute for a single vehicle or 6 psi for a combination vehicle.

Tractor protection valve test: with the trailer supply line disconnected, the trailer spring brakes should apply and the tractor protection valve should close, preventing air loss.

Slack adjuster check: with the brakes released, the push rod should move no more than 1 inch by hand; with the brakes applied, the push rod angle should be about 90 degrees.

Brake lag: air brakes take about 0.4-0.6 seconds to apply, so stopping distance is longer than with hydraulic brakes; allow extra following distance.

Fifth wheel and kingpin: check that the fifth wheel jaws are locked around the kingpin, the release lever is secured, and the fifth wheel is greased.

Trailer air lines: connect the emergency (supply) line first, then the service line; check that the lines are not crossed or kinked.

Tug test: after coupling, pull forward gently with the trailer brakes locked to confirm the kingpin is locked in the fifth wheel.

Landing gear: fully raised after coupling, with the crank handle secured; the landing gear must not touch the ground while driving.

Trailer brake check: with the tractor brakes released and the trailer brakes applied, the combination should not move; test the trailer spring brakes with the supply line disconnected.

Off-tracking and rearward amplification: the rear trailer of a double or triple swings wider on turns; watch for this when turning or changing lanes.

Jackknife prevention: brake gently on slippery surfaces, avoid abrupt steering, and keep the tractor and trailer aligned; a jackknife occurs when the trailer pushes the tractor sideways.

Swing radius: a combination vehicle's rear wheels cut the corner, so swing wide before turning and watch the trailer's rear in the mirrors.

Hours of service: 11 hours driving after 10 consecutive hours off duty; 14-hour on-duty window; 30-minute break after 8 hours of driving; 60/70-hour limit in 7/8 days.

ELD rule: most interstate drivers must use an electronic logging device to record hours of service; paper logs are allowed only in limited exceptions.

CDL medical card: drivers must carry a current DOT medical examiner's certificate and meet the physical qualification standards.

Drug and alcohol testing: pre-employment, random, post-accident, reasonable suspicion, return-to-duty, and follow-up testing are required; BAC limit is 0.04.

Vehicle inspection report: drivers must review and sign the previous report and certify repairs before operating; keep the report for at least 90 days.

Emergency equipment: fire extinguisher (minimum 5 BC rating), three reflective triangles, and spare fuses are required on most commercial vehicles.

Load securement and weight: obey posted weight limits, bridge formulas, and state permits; overweight vehicles are subject to fines and out-of-service orders.

Incident reporting: report any accident involving injury, death, or disabling damage to the motor carrier immediately; a written report is required within 24 hours in many cases.