MA CDL General Knowledge flashcards

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

Pre-trip inspection purpose

A systematic check of the vehicle before driving that verifies brakes, lights, tires, fluids, and coupling devices are safe, catching defects that could cause a crash or breakdown.

Tire tread minimum

Front steering tires need at least 4/32 inch of tread depth; all other tires need at least 2/32 inch. Worn tires lose traction and increase stopping distance.

Low air pressure warning

A warning device must activate before air pressure drops below 60 psi. If the warning fails to work, the vehicle must not be driven until repaired.

Spring brake application

Spring brakes apply automatically when air pressure drops to between 20 and 45 psi, stopping the vehicle if the air system fails.

Double-clutching

Press the clutch, shift to neutral, release the clutch, press it again, and shift to the next gear so engine and transmission speeds match without clashing.

Progressive shifting

Upshifting at progressively lower engine RPMs as road speed increases, which saves fuel. Do not use it when climbing hills or when extra power is needed.

Off-tracking

The tendency of the rear wheels to follow a shorter path than the front wheels in a turn. Longer wheelbases and trailers increase the amount of off-tracking.

Backing with a helper

Back only when necessary, use a helper positioned outside on the right rear, and stop immediately if you lose sight of the helper.

Signaling distance

Signal at least 100 feet before a turn in a city or business district and at least 200 feet before a turn on a highway or rural road.

No-Zone blind spots

Areas around a large vehicle where the driver cannot see other vehicles: roughly 20 feet ahead, 30 feet behind, and one lane on each side.

Night high-beam dimming

Dim high beams within 500 feet of an oncoming vehicle and within 200 feet when following another vehicle, to avoid blinding other drivers.

Following distance rule

Allow at least one second per 10 feet of vehicle length below 40 mph and add one second per 10 feet above 40 mph. A 60-foot rig at 55 mph needs 7 seconds.

Total stopping distance

The sum of perception distance, reaction distance, brake lag distance, and braking distance. For a loaded 80,000-lb rig at 55 mph it is about a football field.

Downgrade gear selection

Select a gear low enough to descend without continuous braking. Use engine braking and stab braking; never ride the brakes on a long downgrade.

Rear-wheel skid recovery

Stop braking, steer in the direction you want to go, and do not accelerate until the vehicle is under control. Steering into the skid corrects the swing.

Brake fade

Loss of braking power caused by overheated brakes on long downgrades. Prevent it by using a lower gear and stab braking instead of continuous application.

ABS operation

Do not pump the brakes; apply firm, continuous pressure and steer while braking. A pulsing pedal and noise are normal during ABS activation.

Tire blowout response

Hold the steering wheel firmly, stay off the brakes, let the vehicle slow gradually, and pull off the road when it is safe to do so.

Cargo tiedown strength

The combined working load limit of tiedowns must be at least 50 percent of the cargo weight. Cargo over 10,000 lbs requires at least four tiedowns.

Hazardous material placards

Placards are required for 1,001 lbs or more of a Table 2 material or any amount of a Table 1 material, and must appear on all four sides.

Railroad crossing stop distance

Stop between 15 and 50 feet from the nearest rail, look and listen, do not shift gears while crossing, and cross only when you can clear the tracks completely.

CDL BAC limit

The legal limit for commercial motor vehicle operators is 0.04 percent. A first offense brings a one-year disqualification; a second offense brings a lifetime disqualification.

Implied consent

By driving a commercial motor vehicle, you consent to alcohol and drug testing. Refusing a required test results in a one-year disqualification.

Alcohol elimination rate

The body eliminates alcohol at roughly one standard drink per hour. Coffee, cold showers, and exercise do not speed elimination or reduce impairment.

Governor cut-in and cut-out

The air compressor governor cuts the compressor in at about 100 psi and out at about 125 psi, maintaining working air pressure in the system.

Tractor protection valve

A valve that closes and prevents air loss from the tractor if the trailer breaks away, causing the trailer spring brakes to apply automatically.

ABS malfunction lamp

If the ABS lamp stays on, ABS is not working, but normal brakes still function. The vehicle can be driven but should be serviced soon.

14-hour driving window

Driving is not permitted after the 14th consecutive hour on duty, regardless of how much driving time remains within the 11-hour limit.

30-minute break rule

A driver must take at least a 30-minute interruption of driving after 8 cumulative hours of driving without a break.

Whistleblower protection

An employer may not retaliate against an employee who reports a commercial motor vehicle safety violation. Complaints must be filed with OSHA within 180 days.

Massachusetts CDL classes

Class A covers combinations over 26,001 lbs with a towed unit over 10,000 lbs; Class B covers single vehicles over 26,001 lbs; Class C covers small passenger and hazmat vehicles.

CDL endorsements

H is hazardous materials, N is tank vehicles, P is passengers, S is school bus, T is double or triple trailers, and X combines tank and hazardous materials.