Kentucky CDL General Knowledge flashcards

32 cards. Read the term and the definition here. The deck at the top of this page is optional.

Total stopping distance

The sum of perception distance, reaction distance, brake lag distance, and braking distance. At 55 mph a loaded truck needs about the length of a football field to stop.

Following distance rule

At least one second per 10 feet of vehicle length below 40 mph, plus one extra second when over 40 mph. A 60-foot rig at 55 mph needs 7 seconds.

Hydroplaning

Tires lose contact with the road on a wet surface. It can begin at speeds as low as 30 mph. Release the accelerator and avoid hard braking or steering.

Rear-wheel skid correction

Steer in the direction you want the front of the vehicle to go. For a rear-wheel skid, turn the steering wheel toward the skid.

Aggregate working load limit

For cargo over 1,100 pounds, the tiedowns' combined working load limit must be at least 1.5 times the cargo weight.

Tiedown count rule

One tiedown for cargo up to 5 feet and 1,100 pounds; two for 5 to 10 feet or over 1,100 pounds; a fourth for every additional 10 feet.

Rear overhang marking

Cargo extending 4 feet or more beyond the rear of the vehicle needs a red-orange flag or marker in daylight and a red light visible for 500 feet at night.

Cargo securement recheck

Check cargo securement within the first 50 miles and every 150 miles or 3 hours thereafter, and after any emergency stop.

Standee line

A line at least 2 inches wide on the floor, no more than 6 inches behind the driver's seat, marking where passengers may stand on a bus.

School bus railroad stop

Stop the bus 15 to 50 feet before the nearest rail, open the door, listen, and look both ways before proceeding, whether loaded or empty.

Low-air warning

A buzzer and light must activate before air pressure drops below 60 psi. The spring brakes apply automatically between 20 and 45 psi.

Air leak test

Build pressure to 120 psi, shut off the engine, and watch the gauge. Loss should be less than 3 psi per minute for a single vehicle and less than 4 psi per minute for a combination.

Safety valve

A valve that releases air at about 150 psi to protect the air brake system from overpressure.

Fanning the brakes

Applying and releasing the brake repeatedly to reduce air pressure. Use it only for testing the low-air warning and spring brakes, not for stopping.

Trailer air line colors

The emergency (supply) line is typically blue and the service line is red. Glad hands connect the tractor lines to the matching trailer lines.

Tractor protection valve

A valve that closes and prevents air loss from the tractor if the trailer breaks away or air pressure drops.

Off-tracking

The rear wheels of a combination follow a shorter path than the front wheels. A tractor-trailer can off-track 2 to 3 feet or more in a tight turn.

Trailer hand valve

Also called the trolley valve. It operates only the trailer brakes and is used only for testing, never for normal stopping.

Converter dolly

A device with its own air lines and brakes that connects the first trailer to the second trailer on doubles and triples.

Dolly pintle hook

The hook at the rear of a converter dolly that connects to the next trailer. Make sure it is latched and the safety pin is in place.

Doubles backing

Back only the rear trailer if possible. Backing more than one trailer at a time is difficult and usually avoided.

Tank vehicle center of gravity

Tank vehicles have a high center of gravity and a liquid load that shifts. The shifting load can cause rollover, especially in curves or evasive maneuvers.

Baffles

Partitions inside a tank that reduce the movement of liquid but do not eliminate it. A partially filled tank is more dangerous than a full or empty one.

Tanker curve speed

Reduce speed on curves and ramps. Make turns smoothly and avoid sudden steering or braking because the shifting load can push the vehicle into a rollover.

Hazmat endorsement

An H endorsement is required to drive a vehicle carrying hazardous materials that require placards.

Placard threshold

Placards are required for 1,001 pounds or more aggregate gross weight of a hazardous material in one vehicle, and for any amount of certain materials.

Shipping papers

Must be within reach of the driver while driving and include the proper shipping name, hazard class, UN number, and quantity.

Hazmat parking

Park away from people, tunnels, and bridges. Do not park within 5 feet of the traveled portion of a road.

School bus endorsements

A school bus driver must have both a school bus (S) endorsement and a passenger (P) endorsement on the CDL.

Tire tread minimums

At least 4/32 inch on the front steer tires and 2/32 inch on all other tires.

Pre-trip inspection items

Check the engine compartment, lights, tires, brakes, steering, mirrors, and emergency equipment before each trip.

Shifting on downgrades

Shift to a lower gear before starting down a grade to use engine braking and avoid brake fade. Do not coast in neutral.