OR CDL General Knowledge cheat sheet

Pre-trip inspection order: engine compartment (fluid levels, belts, hoses, steering, suspension, brakes, lights, reflectors) → walk-around (tires, wheels, rims, lug nuts, brake adjustment, frame, coupling devices) → in-cab (seat belt, gauges, horn, wipers, mirrors, brakes, lights) → brake test before moving.

Air brake leak-down limits: with engine off and full pressure, pressure loss must be no more than 3 psi in one minute for a single vehicle and no more than 4 psi in one minute for a combination vehicle; a low-air warning must activate by 60 psi.

Air brake buildup: with the engine at operating rpm, pressure must rise from 85 to 100 psi within 45 seconds for a combination vehicle with a dual air system; the compressor governor cut-out is typically near 125 psi.

Stopping distance = perception distance + reaction distance + brake lag distance + braking distance. At 55 mph on dry pavement, total stopping distance for a loaded tractor-trailer is roughly the length of a football field (about 300 feet).

Speed and following distance: below 40 mph, follow at least one second per 10 feet of vehicle length plus one second; at 40 mph and above, add one extra second. A 60-foot combination at 55 mph needs at least 7 seconds.

Hazardous materials placards are required for 1,001 pounds or more of a Table 2 material, any amount of a Table 1 material, 1.1 gallons of a Table 4 liquid, or 220 pounds of Table 3 material; placards go on both sides and both ends.

Railroad-highway grade crossings: never shift gears while crossing, stop 15 to 50 feet before the nearest rail if required, and do not cross until the vehicle has room to clear the tracks completely.

Cargo securement: aggregate working load limit of tiedowns must be at least 50 percent of the cargo weight, and the system must withstand 0.8 g deceleration forward and 0.5 g rearward and laterally for vehicles over 10,000 pounds.

Out-of-service conditions include 20 percent or more of brakes defective, any brake with a missing part or pushrod stroke beyond adjustment limit, cracked or welded brake drums, and air loss exceeding limits; the driver may not move the vehicle until repaired.

Alcohol and drugs: CDL holders are considered driving under the influence at a blood alcohol concentration of 0.04 percent or higher; refusal of a required test results in a one-year CDL disqualification for a first offense.

Disqualification for major offenses (first offense): at least one year for a first conviction of DUI, leaving the scene of a fatal crash, using a vehicle to commit a felony, or driving while suspended for a major offense; lifetime for a second major offense.

Serious traffic violations: two convictions in three years disqualify for 60 days, three in three years disqualify for 120 days; serious violations include excessive speeding (15 mph or more over the limit), reckless driving, and improper lane changes.

Hours of service for property-carrying drivers: 11-hour driving limit and 14-hour on-duty window after 10 consecutive hours off duty, a 30-minute break after 8 cumulative driving hours, and a 60/70-hour limit in 7/8 consecutive days.

Emergency equipment required: at least one fire extinguisher (10 BC or larger for a bus or hazmat vehicle), spare fuses, three reflective warning triangles (or six fusees), and a properly charged and rated fire extinguisher mounted securely.

Skid recovery: stop braking, keep both hands on the wheel, and steer in the direction you want the vehicle to go; do not turn the steering wheel sharply or apply the brakes on the rear wheels to correct a rear-wheel skid.

Mountain driving: select a gear low enough to hold the descent without using the brakes, descend at a speed no faster than the ascent speed, and use the snub-braking technique rather than continuous braking to avoid brake fade.

Shifting and speed: do not coast with the clutch depressed or in neutral, and do not shift gears while on a railroad crossing or bridge; double-clutch or use the progressive shift pattern for non-synchronized transmissions.

Tire and wheel inspection: reject tires with tread depth below 4/32 inch on front wheels or 2/32 inch on other wheels, tread separation, or sidewall cuts; check for missing or loose lug nuts, cracks, and rust streaks around wheel nuts.

Hazardous materials classes: Class 1 explosives, Class 2 gases (2.1 flammable, 2.2 nonflammable, 2.3 toxic), Class 3 flammable liquids, Class 4 flammable solids, Class 5 oxidizers, Class 6 toxic and infectious substances, Class 7 radioactive, Class 8 corrosives, Class 9 miscellaneous.

Hazmat communication: shipping papers must be within the driver's reach or in a holder on the driver's door, placards must match the hazard class and be displayed on both sides and both ends, and emergency response information must accompany the shipment.

Loading and unloading: never smoke within 25 feet of a placarded vehicle, keep the engine off during loading or unloading of explosives or flammable materials, and do not load Division 1.1 or 1.2 explosives with detonators or other hazardous materials.

Parking a placarded vehicle: park at least 5 feet from the traveled portion of the road, do not park within 300 feet of a bridge, tunnel, or open fire, and never park within 5 feet of a railroad track.

Brake inspection for combination vehicles: check the tractor protection valve, trailer hand valve, and emergency air line; a trailer that loses air pressure must apply its spring brakes automatically.

Coupling and uncoupling: back under the trailer slowly, listen for the click of the fifth-wheel jaws, tug-test the coupling with the trailer brakes set, and connect the emergency line first and disconnect it last.

Lane changes and turns: signal at least 100 feet before a turn, swing wide or use a buttonhook turn for a long wheelbase, and check both mirrors and the blind spot before changing lanes.

Night driving and visibility: dim high beams within 500 feet of an oncoming vehicle or when following within 200 feet, and use low beams in fog, rain, or snow because high beams reflect glare back at the driver.

Reportable crashes: notify the nearest police authority immediately and, for a crash involving hazardous materials, report to the National Response Center at 1-800-424-8802 as soon as possible.

Pre-trip brake test: with the parking brake released and the engine running, apply the foot brake and hold for one minute while watching the air gauge; a loss of more than 3 psi in one minute (single) or 4 psi (combination) indicates a leak.

Low-air warning test: pump the brake pedal to reduce pressure; the warning buzzer or light must come on before pressure drops below 60 psi, and the spring brakes must fully engage by 20 to 45 psi.

Tire contact patch and load: underinflation is the leading cause of tire failure; check pressure when tires are cold, and reject tires with bulges, knots, or exposed fabric or cord.

Following distance in poor conditions: double the normal following distance in rain, and increase it further in snow, ice, or fog; stopping distance on ice can be ten times greater than on dry pavement.

Railroad crossing procedure: turn on four-way flashers, check for a clear path, use the lowest gear that will cross without shifting, and if the vehicle stalls on the tracks, get out and move away immediately, then call the railroad or 911.

Cargo inspection: inspect cargo and tiedowns within the first 50 miles of a trip, then every 150 miles or every 3 hours of driving, whichever comes first, and after any change in loading.

Fuel and fire safety: shut off the engine before fueling, do not smoke near fueling operations, and know that a fire extinguisher rated 10 BC is the minimum for a placarded vehicle.

Distracted driving and cell phones: a CDL holder may not use a hand-held mobile phone while driving, and texting while driving is a primary offense that can lead to disqualification.

Medical certification: a CDL holder must maintain a current medical examiner's certificate and self-certify the type of driving; a medical variance may be required for certain vision or insulin-treated diabetes cases.

Vehicle inspection report: a driver must prepare a written report at the end of each day's work on a vehicle with a defect, and the carrier must repair any defect that affects safe operation before the vehicle is dispatched again.

Emergency stops and warning devices: place reflective triangles within 10 minutes of stopping, at 10 feet, 100 feet, and 200 feet behind the vehicle on a two-lane road; use the same pattern ahead and behind on a divided highway.

Right-of-way and intersections: a commercial vehicle needs more time and distance to stop, so scan 12 to 15 seconds ahead and cover the brake when approaching an intersection with a stale green light.

Backing safety: back only when necessary, use a helper or spotter when available, and get out and look if unsure; back toward the driver's side when possible to keep the blind area smaller.

Hazardous materials parking and routes: follow designated routes, avoid tunnels and heavily populated areas when required, and never leave a placarded vehicle unattended unless the vehicle is secured and the materials are protected.

Air brake system components: the compressor, governor, air tanks, foot valve, slack adjusters, and spring brakes work together; the supply line charges the trailer and the control line signals the trailer brakes.

Skid and off-road recovery: if a wheel drops off the pavement, hold the wheel firmly, slow gradually, and steer back onto the pavement only after slowing to a safe speed; do not jerk the wheel.

Speed management on curves: reduce speed before entering a curve, and remember that the posted advisory speed is for cars; a loaded truck may need to go slower to avoid a rollover.

Driver qualification file: a motor carrier must keep a driver qualification file including the application, motor vehicle record, road test or equivalent, medical certificate, and annual review.

Pre-trip lighting check: verify headlights (high and low beams), parking lights, clearance lights, turn signals, four-way flashers, brake lights, and backup lights, and confirm reflectors are clean and unbroken.

Steering and suspension inspection: check the steering wheel for excessive play (more than 10 degrees free play), inspect the tie rod and drag link for looseness, and look for cracked or broken leaf springs and missing spring hangers.

Fifth-wheel and kingpin: check that the fifth-wheel jaws are locked around the kingpin, the release lever is secured, and the mounting bolts are tight; a gap between the apron and the fifth wheel indicates improper coupling.

Pre-trip exhaust and engine check: look for exhaust leaks, check the coolant and oil levels, inspect belts for cracks and glazing, and confirm the engine has no fluid leaks underneath.

Brake adjustment: with the brakes released, check pushrod travel against the adjustment limit; a pushrod stroke beyond the limit means the brake is out of adjustment and the vehicle is out of service.

Hazardous materials emergency response: use the emergency response guidebook to identify the material, isolate the area, and do not attempt to fight a fire involving explosives or a large flammable liquid spill.

Alcohol and drug testing: a CDL driver is subject to pre-employment, random, post-accident, reasonable suspicion, return-to-duty, and follow-up testing under federal rules.

Tire chains and winter driving: install chains on the drive tires when required by signs, keep speed below 30 mph with chains, and remember that chains improve traction but do not shorten stopping distance on ice.

Traffic and speed: obey posted speed limits, reduce speed in work zones, and remember that a commercial vehicle's speed must be reasonable for conditions even when below the posted limit.

Air brake dual system: the primary system operates the rear brakes and the secondary system operates the front brakes; a loss of one system still leaves braking on the other, but stopping distance increases.

Spring brake operation: spring brakes apply automatically when air pressure drops to between 20 and 45 psi, and they can be released manually with a release bolt for towing or repair.

Trailer air line connections: the emergency (supply) line is typically the larger coupler and the service (control) line the smaller one; crossed lines can cause the trailer brakes to drag or fail to release.

Cargo weight and axle limits: know the gross vehicle weight rating, gross combination weight rating, and axle weight limits, and distribute cargo so no axle is overloaded.

Hazardous materials segregation: do not load cyanides or acids with acids, do not load oxidizers with flammables, and do not load Division 1.1 or 1.2 explosives with any other hazardous material.

Pre-trip brake warning devices: check that the low-air warning works, the parking brake holds, and the service brake stops the vehicle without pulling to one side.

Following and passing: never pass on a hill or curve where visibility is limited, and allow extra space when passing because a loaded truck accelerates slowly and needs a long distance to complete the pass.

Fatigue and hours of service: a driver must take a 30-minute break after 8 cumulative hours of driving, and the 14-hour window cannot be extended by breaks or off-duty time.

Roadside inspection: a driver must present the CDL, medical certificate, and shipping papers when requested, and must comply with out-of-service orders before moving the vehicle.

Skid prevention: maintain proper tire pressure and tread, slow down on wet or icy roads, and avoid sudden braking or steering inputs that break traction.

Hazardous materials shipping papers: the papers must show the proper shipping name, hazard class, identification number, total quantity, and emergency response telephone number.

Pre-trip coupling check: after coupling, tug-test with the trailer brakes set, visually confirm the jaws are closed, and connect the air lines and electrical cord before raising the landing gear.

Emergency warning device placement: on a divided highway, place triangles at 10 feet, 100 feet, and 200 feet behind the vehicle and also ahead if traffic approaches from both directions.

Speed and stopping on grades: downshift before starting a descent, use the same gear going down as going up, and brake early rather than riding the brakes.

Cargo securement devices: use tiedowns with a working load limit at least half the cargo weight, and use at least two tiedowns for articles longer than 5 feet or weighing more than 1,100 pounds.

Driver health and vision: a CDL driver must meet vision standards (usually 20/40 in each eye with or without correction) and maintain a current medical examiner's certificate.

Railroad crossing and hazmat: a placarded vehicle must stop at all railroad crossings unless the crossing is exempt, and must not cross until the tracks are clear.

Backing and blind spots: use mirrors, get out and look, and use a spotter; a tractor-trailer has large blind spots directly behind and along both sides.

Pre-trip inspection documentation: complete a written vehicle inspection report each day, listing any defects found, and ensure defects are repaired before the vehicle is operated again.

Air brake compressor check: with the engine running, build pressure to the governor cut-out and confirm the compressor stops; a compressor that will not build pressure indicates a serious defect.

Hazardous materials placarding: placards must be displayed on both sides and both ends of the vehicle, and the placard must match the hazard class of the material being carried.

Speed and following distance on ice: reduce speed well below the posted limit and increase following distance to at least double the normal dry-road distance.

Emergency equipment and fire: know the location of the fire extinguisher, check its charge monthly, and remember that a fire involving hazardous materials may require evacuation rather than fighting.

Loading and weight distribution: place heavy cargo over the drive axles when possible, secure it against shifting, and never exceed the gross vehicle weight rating or axle ratings.

Traffic laws and right-of-way: a commercial vehicle must yield to pedestrians, emergency vehicles, and trains, and must stop for school buses with flashing red lights unless separated by a median.

Pre-trip tire check: check tire pressure, tread depth, and sidewall condition, and verify lug nuts are tight and free of rust streaks that indicate looseness.

Driver disqualification and records: serious traffic violations and major offenses lead to disqualification periods, and the driver must notify the employer of any conviction within 30 days.

Hazardous materials loading: do not smoke within 25 feet of a placarded vehicle, keep the engine off during loading or unloading of explosives or flammables, and use a trained person to load or unload.

Pre-trip air brake test sequence: check the low-air warning, the spring brake application, the leak-down rate, and the buildup rate before moving the vehicle.

Following distance and visibility: use the 7-second rule for a 60-foot combination at 55 mph, and increase it in rain, snow, fog, or darkness.

Cargo tiedown spacing: tiedowns must be spaced no more than 10 feet apart for articles longer than 5 feet, and the aggregate working load limit must be at least 50 percent of the cargo weight.

Emergency response and reporting: report a hazardous materials spill to the National Response Center, and report a crash to the nearest police authority immediately.

Pre-trip steering check: check the steering wheel for excessive free play, inspect the tie rod and drag link, and confirm the power steering operates without noise or binding.

Speed management and curves: reduce speed before entering a curve, and remember that a loaded truck has a higher center of gravity and is more prone to rollover.

Driver qualification and medical: maintain a current medical examiner's certificate, self-certify the type of driving, and keep the qualification file current with the employer.

Railroad crossing safety: never shift gears while crossing, stop 15 to 50 feet before the nearest rail if required, and do not cross until the vehicle can clear the tracks completely.

Pre-trip inspection of the engine compartment: check the oil, coolant, power steering fluid, and windshield washer fluid levels, and inspect belts and hoses for cracks, glazing, and leaks.

Air brake leak-down and buildup: the system must lose no more than 3 psi per minute (single) or 4 psi per minute (combination), and must build from 85 to 100 psi within 45 seconds.

Hazardous materials classes and placards: match the placard to the hazard class, and remember that 1,001 pounds or more of a Table 2 material requires placards.

Following distance and speed: use at least one second per 10 feet of vehicle length plus one second, and add an extra second at speeds of 40 mph or higher.

Cargo securement: use at least two tiedowns for articles longer than 5 feet or weighing more than 1,100 pounds, and ensure the aggregate working load limit is at least 50 percent of the cargo weight.

Emergency warning devices: place reflective triangles at 10 feet, 100 feet, and 200 feet behind the vehicle within 10 minutes of stopping.

Driver disqualification: a first major offense disqualifies for at least one year, and a second major offense disqualifies for life.

Hours of service: the 11-hour driving limit and 14-hour on-duty window apply after 10 consecutive hours off duty, with a 30-minute break after 8 cumulative driving hours.

Railroad crossing procedure: turn on four-way flashers, check for a clear path, use the lowest gear that will cross without shifting, and get out and move away if the vehicle stalls on the tracks.

Pre-trip inspection of the walk-around: check tires, wheels, rims, lug nuts, brake adjustment, frame, coupling devices, lights, and reflectors.

Air brake system components: the compressor, governor, air tanks, foot valve, slack adjusters, and spring brakes work together, and the supply line charges the trailer while the control line signals the trailer brakes.

Hazardous materials parking: park at least 5 feet from the traveled portion of the road, do not park within 300 feet of a bridge, tunnel, or open fire, and never park within 5 feet of a railroad track.

Skid recovery: stop braking, keep both hands on the wheel, and steer in the direction you want the vehicle to go.

Mountain driving: select a gear low enough to hold the descent without using the brakes, descend at a speed no faster than the ascent speed, and use snub braking.

Tire inspection: reject tires with tread depth below 4/32 inch on front wheels or 2/32 inch on other wheels, and check for tread separation and sidewall cuts.

Night driving: dim high beams within 500 feet of an oncoming vehicle or when following within 200 feet, and use low beams in fog, rain, or snow.

Reportable crashes: notify the nearest police authority immediately and report a hazardous materials release to the National Response Center.

Cell phone and texting: a CDL holder may not use a hand-held mobile phone while driving, and texting while driving can lead to disqualification.

Pre-trip inspection order: engine compartment, walk-around, in-cab, and brake test before moving the vehicle.

Air brake low-air warning: the warning buzzer or light must come on before pressure drops below 60 psi, and the spring brakes must fully engage by 20 to 45 psi.

Hazardous materials segregation: do not load cyanides or acids with acids, do not load oxidizers with flammables, and do not load Division 1.1 or 1.2 explosives with any other hazardous material.

Following distance in poor conditions: double the normal following distance in rain, and increase it further in snow, ice, or fog.

Cargo inspection: inspect cargo and tiedowns within the first 50 miles of a trip, then every 150 miles or every 3 hours of driving, whichever comes first.

Emergency equipment: at least one fire extinguisher (10 BC or larger for a bus or hazmat vehicle), spare fuses, and three reflective warning triangles or six fusees.

Disqualification for serious traffic violations: two convictions in three years disqualify for 60 days, and three in three years disqualify for 120 days.

Railroad crossing and hazmat: a placarded vehicle must stop at all railroad crossings unless the crossing is exempt.

Backing safety: back only when necessary, use a helper or spotter when available, and get out and look if unsure.

Pre-trip inspection of the in-cab: check the seat belt, gauges, horn, wipers, mirrors, brakes, and lights.

Air brake buildup: with the engine at operating rpm, pressure must rise from 85 to 100 psi within 45 seconds for a combination vehicle with a dual air system.

Hazardous materials communication: shipping papers must be within the driver's reach or in a holder on the driver's door, and emergency response information must accompany the shipment.

Stopping distance: total stopping distance equals perception distance plus reaction distance plus brake lag distance plus braking distance.

Cargo securement devices: use tiedowns with a working load limit at least half the cargo weight, and use at least two tiedowns for articles longer than 5 feet or weighing more than 1,100 pounds.

Emergency warning device placement: on a divided highway, place triangles at 10 feet, 100 feet, and 200 feet behind the vehicle and also ahead if traffic approaches from both directions.

Hours of service: a driver must take a 30-minute break after 8 cumulative hours of driving, and the 14-hour window cannot be extended by breaks or off-duty time.

Roadside inspection: a driver must present the CDL, medical certificate, and shipping papers when requested.

Skid prevention: maintain proper tire pressure and tread, slow down on wet or icy roads, and avoid sudden braking or steering inputs.

Pre-trip inspection of the engine compartment: check the oil, coolant, power steering fluid, and windshield washer fluid levels, and inspect belts and hoses for cracks, glazing, and leaks.

Air brake leak-down and buildup: the system must lose no more than 3 psi per minute (single) or 4 psi per minute (combination), and must build from 85 to 100 psi within 45 seconds.

Hazardous materials classes and placards: match the placard to the hazard class, and remember that 1,001 pounds or more of a Table 2 material requires placards.

Following distance and speed: use at least one second per 10 feet of vehicle length plus one second, and add an extra second at speeds of 40 mph or higher.

Cargo securement: use at least two tiedowns for articles longer than 5 feet or weighing more than 1,100 pounds, and ensure the aggregate working load limit is at least 50 percent of the cargo weight.

Emergency warning devices: place reflective triangles at 10 feet, 100 feet, and 200 feet behind the vehicle within 10 minutes of stopping.

Driver disqualification: a first major offense disqualifies for at least one year, and a second major offense disqualifies for life.

Hours of service: the 11-hour driving limit and 14-hour on-duty window apply after 10 consecutive hours off duty, with a 30-minute break after 8 cumulative driving hours.

Railroad crossing procedure: turn on four-way flashers, check for a clear path, use the lowest gear that will cross without shifting, and get out and move away if the vehicle stalls on the tracks.