MI CDL General Knowledge cheat sheet

Total stopping distance = perception distance + reaction distance + brake lag distance + braking distance; at 55 mph a loaded rig needs roughly the length of a football field on dry pavement.

Perception distance is the distance traveled from seeing a hazard until the brain registers it; reaction distance is travel during the time from recognition to applying the brake.

Brake lag distance for air brakes adds about 32 feet at 55 mph because air must travel through lines before the brakes engage; hydraulic brakes have no comparable lag.

Speed limit reductions: 3 mph below posted limit on any grade steep enough to slow a heavy vehicle, and 5 mph below on any curve.

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

A 70-foot combination at 55 mph needs at least 8 seconds of following distance; a 50-foot vehicle needs at least 6 seconds.

Hydroplaning begins at speeds as low as 30 mph with low tread or standing water; release the accelerator and avoid braking hard.

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

Railroad crossings: never shift gears while crossing tracks; if your vehicle stalls, get everyone out and away before calling for help.

Cargo must be secured so it cannot shift or fall; the combined weight of tiedown assemblies must equal at least 50% of the cargo weight.

Each tiedown must be attached to the vehicle and the cargo, and must be able to hold 1.5 times the working load limit of the assembly.

Aggregate working load limit rules: 50% of cargo weight for cargo under 10 feet long or 1,100 lb; 25% for longer or heavier loads.

Front-end structure of the cargo space must be able to contain the cargo if it shifts forward; rear structure must withstand 50% of cargo weight.

Never overload axles, tires, or the gross vehicle weight rating; check weight limits before loading.

Before driving, inspect cargo and tiedowns; recheck within the first 50 miles and every 150 miles or 3 hours thereafter.

Cargo must not obscure lights, reflectors, rear-view mirrors, or the license plate; red flags are required on overhanging loads.

For oversized loads, stop and recheck tiedowns after the first 50 miles, then every 150 miles or 3 hours.

A dual air brake system has two separate circuits; a loss of pressure in one circuit should still leave the other operable.

Normal operating pressure is 100-125 psi; the low-air warning buzzer or light must activate before pressure drops below 60 psi.

The governor cuts the compressor in at about 85 psi and out at about 125 psi; pressure should build from 85 to 100 psi within 45 seconds.

The spring brakes apply automatically when air pressure drops to 20-45 psi; the parking brake knob pops out when pressure is too low.

The static leak test: with engine off and brakes released, pressure should not drop more than 3 psi in one minute; with brakes applied, no more than 4 psi per minute.

The safety valve releases at about 150 psi; if it releases below 150 psi, the system needs repair.

In a dual system, the low-air warning must activate before pressure drops below 60 psi; if it fails, the vehicle is out of service.

Air brake lag: at 55 mph, brake lag alone adds about 32 feet; pump the brakes to test for a leak, then release and listen for leaks.

Three required inspection types: pre-trip (before driving), en route (during the trip), and post-trip (after the trip).

Pre-trip inspection covers engine compartment, cab, lights, walk-around, and brake checks; it must be done within the last 24 hours.

CDL pre-trip inspection includes a check of the engine compartment for fluid levels, belts, hoses, and steering components.

During the walk-around, check tires for tread depth (4/32 inch on front tires, 2/32 inch on other tires), inflation, and damage.

Check that all lights, reflectors, and the horn work; verify the parking brake, service brake, and emergency brake function.

En route inspection: check cargo and tiedowns within the first 50 miles, then every 150 miles or 3 hours.

Post-trip inspection must be completed at the end of each workday and reported; defects affecting safety must be noted and repaired.

Brake test: with engine running and air pressure at normal, release parking brake and apply service brake; the vehicle should stop without pulling to one side.

Use the accelerator, brake, and steering smoothly; sudden movements can cause a skid or loss of control, especially with a heavy load.

On a curve, slow down before entering, maintain a steady speed through the curve, and accelerate gently after the curve.

When stopping, apply the brake gradually and release slightly just before coming to a complete stop to avoid a jerky stop.

To back safely, use a helper and get out to check the area first; if no helper, back slowly and check mirrors frequently.

Start in the proper gear: a heavy vehicle should start in a low gear; never coast in neutral.

Use the parking brake when parked; on a hill, chock the wheels and turn wheels toward the curb or away from traffic.

Avoid oversteering and understeering; keep both hands on the wheel and look ahead to anticipate steering needs.

When driving a vehicle with an automatic transmission, use the lowest gear for steep downgrades to prevent brake fade.

Shift up and down in the proper sequence; never skip gears when downshifting unless the transmission is designed for it.

Double-clutching is required in some non-synchronized transmissions: press clutch, shift to neutral, release clutch, press clutch again, shift to gear.

When shifting, match engine speed to road speed to avoid grinding gears and to maintain control.

Look ahead 12-15 seconds to identify hazards; scan mirrors every 5-8 seconds and check blind spots before changing lanes.

Hazard categories: road conditions, weather, traffic, and vehicle condition; identify and respond early.

On a downgrade, use a lower gear and engine braking; do not ride the brakes, which can cause brake fade.

When approaching a hazard, reduce speed early and be prepared to stop; do not wait until the last moment.

When shifting a manual transmission, keep both hands on the wheel except when shifting; return your hand to the wheel immediately after shifting.

Use turn signals at least 100 feet before turning, and signal early to give other drivers time to react.

Use four-way flashers when driving slowly (below 40 mph) or when stopped in a hazardous position.

Keep a space cushion around your vehicle: at least one car length for each 10 mph of speed in front, and avoid driving in others' blind spots.

When being passed, maintain speed and position; do not speed up or move toward the passing vehicle.

Use your horn only to warn others of danger, not to express frustration; flash headlights to signal presence at night.

When following a large vehicle, stay back so you can see its mirrors and the driver can see you; pass quickly and safely.

At intersections, check left-right-left before proceeding; make eye contact with other drivers when possible.

Space management: allow extra following distance in bad weather, at night, and when carrying a heavy load.

Property-carrying drivers: 11-hour driving limit after 10 consecutive hours off duty; 14-hour on-duty window; 60/70-hour limit in 7/8 consecutive days.

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

The 34-hour restart resets the 60/70-hour cycle; drivers must have 34 consecutive hours off duty.

Sleep debt and fatigue impair reaction time and judgment; take rest breaks and do not drive when drowsy.

Fatigue warning signs: frequent yawning, heavy eyes, drifting, missing exits, and difficulty focusing; stop and rest if these occur.

Daily logbooks must be accurate and current; falsifying logs is a serious violation.

Passenger-carrying drivers: 10-hour driving limit after 8 consecutive hours off duty; 15-hour on-duty window; 60/70-hour limit.

The 14-hour window does not stop for breaks; any off-duty time does not extend the 14-hour window.

CDL holders are subject to a 0.04% BAC limit; a violation results in disqualification and possible license suspension.

Refusing a BAC test results in automatic disqualification for at least one year for a first offense.

Alcohol and drugs impair judgment, coordination, and reaction time; even small amounts increase crash risk.

Prescription and over-the-counter drugs can impair driving; check labels and consult a doctor before driving.

Marijuana, even where legal, is prohibited for CDL drivers and can result in disqualification.

Wellness: get enough sleep, eat properly, exercise, and manage stress; fatigue and illness increase crash risk.

A driver with a detectable alcohol concentration or who refuses testing must be removed from safety-sensitive duties.

Suspension of a CDL for a first alcohol violation is at least one year; for a second, lifetime disqualification.