MA CDL General Knowledge cheat sheet

Pre-trip inspection must cover: engine compartment (fluid levels, belts, hoses, steering, exhaust, battery), walk-around (lights, tires, wheels, mud flaps, frame, coupling devices), and in-cab (gauges, horn, wipers, mirrors, seat belt, parking brake).

Tire tread minimums: 4/32 inch for front steering tires, 2/32 inch for all other tires; check for cuts, bulges, recaps, and proper inflation.

Brake test sequence at start: set parking brake, release trailer spring brakes, pull against parking brake in low gear to test tractor protection valve and brake hold; then perform a 3-point brake test (applied, released, warning).

Air pressure loss limits: with engine off and brakes released, loss must not exceed 3 psi/minute (single vehicle) or 4 psi/minute (combination); with brakes applied, 3 psi/minute.

Low air pressure warning must activate before pressure drops below 60 psi; the spring brakes must apply automatically between 20 and 45 psi.

Slack adjuster check: with brakes released, pull rod should move no more than 1 inch; with brakes applied, no more than 1 inch of travel (some references use a 45-degree angle rule).

Steering wheel play should not exceed 10 degrees (about 2 inches at the rim) on power steering, 10 degrees on manual steering.

Hydraulic brake pedal should not travel more than 75 percent of the way to the floor; if it does, the system needs service before driving.

After a 10-minute hold test, air pressure should not drop more than 3 psi for a single vehicle or 4 psi for a combination.

Double-clutching: press clutch, shift to neutral, release clutch, press clutch again, shift to next gear - matches engine and transmission speeds to avoid gear clash.

Upshift pattern for a typical 10-speed: 1L, 1H, 2L, 2H, 3L, 3H, 4L, 4H, 5L, 5H; downshift in reverse order using the same double-clutch technique.

Progressive shifting means upshifting at lower RPMs as speed increases to save fuel; it should not be used when climbing hills or when extra power is needed.

Backing rule: back only when necessary, use a helper outside the vehicle on the right rear, and if you lose sight of the helper, stop immediately.

Back toward the driver's side when possible so the rear of the trailer swings toward the left and stays visible in the left mirror.

Right turns: swing wide to the left to keep the rear wheels from off-tracking over the curb; left turns: approach from the right lane and turn into the leftmost legal lane.

Off-tracking: the rear wheels follow a shorter path than the front wheels; the longer the wheelbase and trailer, the greater the off-tracking distance.

When backing a tractor-trailer, steer in the opposite direction of the desired trailer movement - turn the wheel right to move the trailer left.

Mirror use: check both mirrors every 5 to 8 seconds; adjust so that a small part of the vehicle is visible in each mirror to establish reference points.

Blind spots: large vehicles have blind spots to the front, sides, and rear; the No-Zone areas extend roughly 20 feet ahead, 30 feet behind, and one lane on each side.

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.

Use four-way flashers when driving slowly (below 40 mph on a highway), when stopped on the shoulder, and when backing or in a hazard.

Tap the brakes to warn following drivers when slowing; use the horn only to warn of danger, not to express frustration.

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

Before changing lanes, check mirrors, signal, check the blind spot, and ensure you can see the rear wheels of the vehicle ahead in your mirrors before completing the move.

Headlights must be on from 30 minutes after sunset to 30 minutes before sunrise, and whenever wipers are in continuous use due to weather.

Following distance: at least one second per 10 feet of vehicle length at speeds under 40 mph; add one second for each 10 feet over 40 mph. A 60-foot vehicle at 55 mph needs at least 7 seconds.

Stopping distance = perception distance + reaction distance + brake lag distance + braking distance; total stopping distance for a loaded 80,000-lb rig at 55 mph is roughly the length of a football field.

Speed limits: 55 mph on most Massachusetts highways, 65 mph on the Massachusetts Turnpike and some rural interstates; posted limits govern commercial vehicles unless a lower limit applies.

The 4-second rule for following at highway speed; increase to 6 or more seconds in rain, snow, fog, or when following motorcycles or vehicles carrying hazardous materials.

Space cushion: keep at least one lane of space on each side when possible; if a vehicle is tailgating, increase your following distance ahead so you can slow gradually.

Bridge height: posted clearance is the maximum; if your vehicle is within 6 inches of the posted height, do not attempt to pass under.

Downgrade rule: select a gear low enough that you can descend without using the brakes continuously; use engine braking and stab braking, never ride the brakes.

Speed and weight: total stopping distance increases with the square of speed; doubling speed roughly quadruples braking distance.

Skid recovery: stop braking, steer in the direction you want to go, and do not accelerate until the vehicle is under control.

Types of skids: front-wheel skid (vehicle won't steer - release brakes and steer), rear-wheel skid (rear swings out - steer into the skid), and power skid (too much throttle - ease off).

Brake fade: caused by overheating brakes on long downgrades; prevent by using a lower gear and stab braking rather than continuous application.

Stab braking: apply brakes fully, release when wheels roll, reapply - repeat as needed; do not use on slippery surfaces or with ABS.

ABS: do not pump the brakes; apply firm, continuous pressure and steer while braking; expect a pulsing pedal and noise.

Tire blowout: hold the steering wheel firmly, stay off the brakes, let the vehicle slow gradually, and pull off the road when safe.

Fire: pull off the road, stop the engine, get passengers out, and call 911; never open the hood if the fire is in the engine compartment - use the fire extinguisher through the grille or from a safe distance.

Engine overheating: turn off the air conditioner, turn on the heater, and pull off the road; do not open the radiator cap while the engine is hot.

If the vehicle becomes stuck on railroad tracks, get everyone out and move away from the tracks at a 45-degree angle in the direction of the approaching train.

Cargo securement: aggregate working load limit of tiedowns must be at least 50 percent of the cargo weight; for cargo over 10,000 lbs, use at least four tiedowns.

Tiedown spacing: for cargo over 5 feet but under 10 feet, use at least two tiedowns; for cargo 10 feet or longer, use one tiedown every 10 feet.

Front-end structure: cargo must be secured so it cannot shift forward more than 1 foot; cargo must not obscure lights, reflectors, or the license plate.

Hazardous materials: placards are required for 1,001 lbs or more of a Table 2 material, or any amount of a Table 1 material; placards must be on all four sides.

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

Vehicles required to stop at railroad crossings: buses carrying passengers, school buses, and vehicles carrying hazardous materials or certain quantities of chlorine.

Hazard awareness: scan 12 to 15 seconds ahead in urban areas and 20 to 25 seconds on highways; check mirrors frequently and watch for vehicles entering from side roads.

Overhead clearance: know your vehicle's height, including the load; if in doubt, stop and check before proceeding.

CDL BAC limit: 0.04 percent for commercial motor vehicle operators; a first offense results in a one-year disqualification, and a second offense results in a lifetime disqualification.

Refusal to submit to a required alcohol or drug test results in a one-year disqualification for the first refusal and a lifetime disqualification for a second.

Implied consent: by driving a CMV, you consent to alcohol and drug testing; refusal is itself a violation.

Alcohol dissipates at roughly one standard drink per hour; coffee, cold showers, and exercise do not speed elimination.

Prescription and over-the-counter drugs: check with a doctor or pharmacist about effects on driving; antihistamines, sleep aids, and some cold medicines can cause drowsiness.

Driver fitness: get at least 7 to 8 hours of sleep, take breaks every 2 hours, and do not drive when fatigued; fatigue impairs reaction time as much as alcohol.

Medical certification: a CDL holder must carry a current medical examiner's certificate; certain medical conditions (epilepsy, insulin-dependent diabetes, vision below 20/40 corrected) require a waiver.

Air brake system components: compressor, governor, air tanks (wet, primary, secondary), safety valve, alcohol evaporator, and slack adjusters.

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

Dual air brake system: the primary system operates the rear brakes; the secondary system operates the front brakes; a loss in one system still leaves the other operable.

The tractor protection valve closes and prevents air loss from the tractor if the trailer breaks away; the trailer spring brakes apply automatically.

Antilock braking system (ABS): a malfunction lamp that stays on means ABS is not working, but normal brakes still function; the vehicle can still be driven but should be serviced.

Cooling system: check coolant level at the reservoir, not by removing the radiator cap when hot; check belts for cracks and proper tension.

Exhaust system: check for leaks, loose clamps, and rust; a carbon monoxide leak can be fatal in the cab.

Electrical system: check battery connections, alternator belt, and all lights (headlights, brake lights, turn signals, clearance lights, and reflectors).

11-hour driving limit: no more than 11 hours of driving after 10 consecutive hours off duty.

14-hour window: driving is not permitted after the 14th consecutive hour on duty, regardless of how much driving time remains.

30-minute break: required after 8 cumulative hours of driving without at least a 30-minute interruption of driving.

60/70-hour limit: no driving after 60 hours on duty in 7 consecutive days or 70 hours in 8 consecutive days; reset with 34 consecutive hours off duty.

Sleeper berth split: drivers may split the required 10 hours off duty into two periods (one at least 7 hours in the sleeper berth, the other at least 2 hours off duty), and the longer period does not count against the 14-hour window.

ELD: most interstate CMV drivers must use an electronic logging device; paper logs are allowed only for short-term exceptions such as a malfunction.

Whistleblower protection: an employer may not retaliate against an employee who reports a violation of a commercial motor vehicle safety regulation; complaints go to OSHA within 180 days.

Penalties: serious traffic violations (excessive speeding, reckless driving, improper lane changes) can result in a 60-day disqualification for a second offense within 3 years.

Massachusetts CDL classes: Class A (combination vehicles over 26,001 lbs with a towed unit over 10,000 lbs), Class B (single vehicles over 26,001 lbs), Class C (vehicles designed to carry 16 or more passengers or hazardous materials).

Endorsements: H (hazardous materials), N (tank vehicles), P (passengers), S (school bus), T (double/triple trailers), X (tank and hazardous materials combined).

Age: a CDL applicant must be at least 18 years old for intrastate driving and 21 for interstate driving; a school bus endorsement requires a minimum age of 21 in Massachusetts.

Knowledge tests: general knowledge, air brakes (if applicable), combination vehicles (Class A), and any endorsement tests; skills tests include pre-trip inspection, basic control, and on-road driving.

Restrictions: an L restriction prohibits driving a CMV with air brakes; an E restriction requires an automatic transmission; an O restriction limits the driver to intrastate operation.

Medical certification: a DOT medical examiner's certificate must be on file with the RMV; a CDL holder must self-certify the type of driving (non-excepted interstate, excepted interstate, or intrastate).

Disqualifications: a DUI, refusing a drug or alcohol test, leaving the scene of an accident, or using a CMV in a felony results in a one-year disqualification (three years if carrying hazardous materials).

Massachusetts CDL renewal: every 5 years; a vision test is required, and drivers 75 and older must pass a vision and medical review.