Arkansas CDL General Knowledge Test cheat sheet

Total stopping distance = perception distance + reaction distance + brake lag distance + braking distance.

Perception distance is the distance traveled from seeing a hazard until the brain recognizes it; at 55 mph this is about 60 feet.

Reaction distance is the distance traveled from recognizing a hazard until the foot hits the brake; at 55 mph this is about 61 feet.

Brake lag distance for air brakes at 55 mph is about 32 feet; hydraulic brakes have no comparable lag.

At 55 mph, total stopping distance for a loaded tractor-trailer with air brakes is roughly 419 feet, about the length of a football field plus.

Speed limits: 55 mph on a two-lane road, 55 mph when carrying hazardous materials, 55 mph when carrying 15 or more passengers.

A vehicle must be placed out of service if the driver is under the influence, ill, or fatigued to the point of being unable to drive safely.

Following distance rule: one second for each 10 feet of vehicle length at speeds under 40 mph; add one second above 40 mph.

A 50-foot combination at 55 mph needs at least 6 seconds of following distance.

Aggregate working load limit of tiedowns = sum of the WLL of all tiedown assemblies used.

Cargo must be secured so it cannot shift or fall; the minimum number of tiedowns is one for articles 5 feet or shorter and 1,100 lb or less.

For articles longer than 5 feet or heavier than 1,100 lb, use at least two tiedowns.

Tiedowns must be placed so that the distance between them is no more than 10 feet for articles over 10 feet long.

Each tiedown must be attached to the vehicle and the cargo; the working load limit of the tiedown system must equal at least half the weight of the cargo.

Front-end structure must withstand a force of 0.8 times the weight of the cargo; rear-end structure 0.5 times the weight.

Cargo must not obscure lights, reflectors, or the license plate, and must not extend more than 3 feet beyond the front bumper.

Cargo extending more than 4 feet beyond the rear must be marked with a red flag or red light in daylight and a red light at night.

A bulkhead is required when cargo could shift forward and crush the cab; it must be strong enough to stop the cargo.

Air brake system pressure must build from 85 to 100 psi within 45 seconds with the engine at fast idle.

With the engine off and the parking brake released, air pressure should not drop more than 3 psi in one minute for a single vehicle, or 4 psi for a combination.

With the engine running and the governor cut out, the system must not lose more than 2 psi in one minute.

The low-air warning must activate before pressure drops below 60 psi; the spring brakes must apply when pressure falls to between 20 and 45 psi.

The safety valve is set to open at 150 psi; the governor cuts out at about 125 psi and cuts in at about 100 psi.

The alcohol evaporator or air dryer removes moisture; drain air tanks daily to remove water and oil.

The supply pressure gauge shows the pressure in the tanks; the application gauge shows the pressure applied to the brakes.

A slack adjuster that moves more than 1 inch (with the brake released) indicates the brakes need adjustment.

The tractor protection valve keeps air in the tractor if the trailer breaks away; it closes at about 20-45 psi.

The tractor protection valve and trailer air supply valve must be checked before driving; the trailer air supply knob pops out when pressure drops.

The fifth wheel should be checked for proper coupling: tug test, visual check of the jaws, and check that the locking lever is secured.

The trailer supply line (emergency line) is red; the service line is blue.

The landing gear must be fully raised before driving; the crank handle must be secured.

Bobtail (tractor only) braking distance is shorter than with a loaded trailer, but the tractor can skid more easily.

When turning a combination vehicle, the rear wheels off-track toward the inside of the turn; the longer the wheelbase, the greater the off-tracking.

The pivot point for a tractor-trailer is the fifth wheel; for a doubles unit, the converter dolly adds a second pivot point.

Before backing a combination vehicle, check that the trailer air lines are not crossed and the trailer brakes are working.

A combination vehicle has a larger blind spot on the right side; the driver should check both mirrors and use a spotter when possible.

The pre-trip inspection has three main parts: engine compartment, walk-around, and in-cab checks.

Check the engine oil level with the dipstick; it should be between the add and full marks.

Check coolant level only when the engine is cool; never open the radiator cap when the engine is hot.

Check the belts for cracks, frays, and proper tension (about 3/4 inch of play).

Check the steering wheel for more than 10 degrees of free play (about 2 inches) before the wheels move.

Check the brake system for leaks, cracked hoses, and proper fluid level; check the slack adjusters and push rods.

Check tire tread depth: at least 4/32 inch for front tires and 2/32 inch for other tires.

Check all lights: headlights, turn signals, brake lights, clearance lights, and reflectors.

Check the emergency equipment: fire extinguisher, spare fuses, and warning triangles (three).

Use the stab braking method for vehicles without ABS: apply the brakes fully, release when wheels lock, and reapply when they roll.

Use controlled braking (squeeze and hold) for vehicles with ABS; do not pump the brakes.

The most important rule for safe driving is to maintain a safe following distance and adjust speed to conditions.

When starting from a stop, release the parking brake only after the engine is running and the vehicle is in gear.

To prevent rollback on a hill, use the parking brake or hold the brake pedal until the clutch engages.

The steering wheel should be held at 9 and 3 o'clock or 8 and 4 o'clock for control.

Use the retarder or engine brake on downgrades to control speed; do not use the service brakes continuously.

When driving a vehicle with a manual transmission, do not coast in neutral; keep the vehicle in gear.

Shift up at the correct RPM; do not over-rev or lug the engine.

Double clutching is required for non-synchronized transmissions: clutch in, shift to neutral, clutch out, clutch in, shift to gear.

When backing, use a spotter and check both mirrors; if you lose sight of the spotter, stop.

Back toward the driver's side (left) when possible for better visibility.

Use the lowest gear when backing a heavy vehicle to maintain control.

When backing a trailer, turn the steering wheel in the direction you want the trailer to go, then follow with the tractor.

Do not back a vehicle unless it is necessary; plan your route to avoid backing.

When shifting a manual transmission, do not skip gears unless the transmission is designed for it.

Use the four-way flashers when driving slowly, when stopped, or when in a hazardous situation.

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

Use turn signals at least 100 feet before a turn; use hand signals if the signals fail.

Check mirrors every 5 to 8 seconds; adjust them before driving.

The blind spot on the right side of a large vehicle is larger than on the left; check it carefully before changing lanes.

Use the horn to warn others of danger; do not use it to express anger.

When passing, signal, check mirrors, and ensure you can see the passed vehicle's headlights before returning to the lane.

Use headlights when driving in rain, fog, or snow, and when visibility is reduced.

The following distance formula: one second for each 10 feet of vehicle length at speeds under 40 mph; add one second above 40 mph.

At 55 mph, a 50-foot combination vehicle needs at least 6 seconds of following distance.

When following a motorcycle, allow at least 4 seconds; motorcycles can stop faster than trucks.

When being passed, maintain speed and keep to the right; do not speed up.

When passing, allow at least 10 seconds to complete the pass.

Reduce speed by 1/3 on wet roads and by 1/2 on packed snow; slow to a crawl on ice.

On a downgrade, select a gear low enough to control speed without using the brakes continuously.

When entering a curve, slow down before the curve and accelerate gently through it.

Use the 3-second rule for cars; for large vehicles, use the length-based formula.

If a tire blows out, hold the steering wheel firmly and avoid braking hard; let the vehicle slow down gradually.

If the brakes fail, downshift and use the parking brake gradually; do not apply it suddenly.

If the vehicle catches fire, stop, turn off the engine, and get everyone out; move away from the vehicle.

If you must stop on a railroad track, get out and run from the tracks; do not try to push the vehicle.

If you are involved in an accident, stop, protect the scene, and call for help; do not leave the scene.

When driving in fog, use low beams and slow down; do not use high beams.

When hydroplaning, ease off the accelerator and do not brake hard; steer straight.

If a vehicle is stuck on a hill, set the parking brake and use wheel chocks before working around it.

Use warning triangles: place one 10 feet behind the vehicle, one 100 feet behind, and one 100 feet ahead on a two-way road.