CDL General Knowledge — All Questions

You arrive for your shift and the tractor was driven by another driver yesterday. Before you move the vehicle, what does the federal rule require you to do first?

• a.Road test the vehicle for at least two miles before loading
• b.Review the last driver vehicle inspection report and be satisfied the vehicle is in safe operating condition✓
• c.Weigh the loaded vehicle at the nearest certified scale
• d.Drain the air tanks and rebuild pressure from zero

A driver must review the previous driver's inspection report and sign it if defects were noted and certified as repaired, then be satisfied the vehicle is safe to operate. Draining tanks completely and rebuilding pressure is not a required daily step, weighing is a cargo issue rather than a pre-trip requirement, and no minimum road-test distance is required before loading.49 CFR §396.13

What is the minimum legal tread depth in a major groove of a front steering-axle tire on a commercial motor vehicle?

• a.6/32 of an inch
• b.2/32 of an inch
• c.1/32 of an inch
• d.4/32 of an inch✓

Steer tires must have at least 4/32 inch of tread in every major groove because they carry the steering and a large share of the load. The 2/32 figure is the minimum for all other tires on the vehicle, and 6/32 and 1/32 are not federal minimums for any position.49 CFR §393.75

During your walkaround you measure 3/32 inch of tread on a drive-axle tire and 5/32 inch on a steer tire. What is the correct conclusion?

• a.The steer tire is illegal but the drive tire is legal
• b.Both tires meet the federal minimum tread requirements✓
• c.Both tires are illegal but the vehicle may be driven to the nearest shop
• d.Both tires are illegal and must be replaced

Non-steering tires need at least 2/32 inch, so 3/32 is legal, and steer tires need at least 4/32 inch, so 5/32 is legal. Neither tire is below the minimum, so no replacement is required and no exception for driving to a shop is needed.49 CFR §393.75

At what air pressure must the low-air-pressure warning device on an air-brake vehicle come on?

• a.At or below 20 psi
• b.At or below 60 psi✓
• c.At or below 85 psi
• d.At or below 45 psi

The low-pressure warning light and buzzer must activate at or before pressure drops to 60 psi, giving the driver time to stop while service brakes still work. Around 85 psi is a typical governor cut-in point, and 20 to 45 psi is the range in which spring brakes apply automatically, which is far too late for a warning.49 CFR §393.51

You are running the air-brake check with a fully charged system, engine off, and the service brakes released. What is the maximum allowable air pressure loss per minute for a combination vehicle?

• a.6 psi per minute
• b.2 psi per minute
• c.4 psi per minute
• d.3 psi per minute✓

With brakes released, a combination vehicle may lose no more than 3 psi per minute; a single vehicle is limited to 2 psi per minute. With the brakes applied the limits rise to 3 psi for a single vehicle and 4 psi for a combination, and 6 psi per minute always indicates an unsafe leak.

With the engine off and the air system fully charged, you begin fanning off air pressure with the brake pedal. At roughly what pressure should the tractor protection valve and parking brake valve pop out?

• a.Between 80 and 100 psi
• b.Between 10 and 15 psi
• c.Between 20 and 45 psi✓
• d.Between 60 and 80 psi

Spring-brake control valves must pop out somewhere between 20 and 45 psi, applying the parking brakes automatically before the system loses the ability to hold the vehicle. Pressures of 60 to 80 psi or higher would mean the valve trips too early, and 10 to 15 psi would leave the vehicle without brakes at a dangerously low pressure.

Which sequence correctly describes the seven-step inspection method?

• a.Start engine, road test, walkaround, engine compartment, cab check, lights, paperwork
• b.Vehicle overview, engine compartment, start engine and check the cab, turn off engine and check lights, walkaround, check signal lights, start engine and check the brake system✓
• c.Check lights, check tires, check brakes, check cargo, check mirrors, check horn, sign the report
• d.Walkaround, engine compartment, brake check, cab check, lights, signals, road test

The standard method starts with a general overview, moves to the engine compartment, then inside the cab, then lights, then the full walkaround, then signal lights, and finishes with the air-brake system check. The other sequences scramble the order or leave out required steps such as the engine compartment and the final brake check.

You finish a run in a property-carrying truck and discover the right rear turn signal stopped working during the trip. What must you do at the end of the day?

• a.Prepare a written driver vehicle inspection report listing the defect and give it to the motor carrier✓
• b.Wait until the defect happens a second time before reporting it
• c.Nothing, because lights are not covered by the inspection report rule
• d.Note it verbally to the next driver only

A driver must prepare a written report whenever a defect or deficiency that could affect safety is discovered, and lighting devices are specifically listed. Verbal notice does not satisfy the recordkeeping requirement, and there is no rule allowing a driver to ignore a defect until it recurs.49 CFR §396.11

Which set of emergency equipment must be on board a commercial motor vehicle?

• a.A first aid kit, a flashlight, and a tire gauge
• b.A tow strap, road flares only, and a hard hat
• c.A properly rated and charged fire extinguisher, spare electrical fuses if the vehicle uses them, and warning devices for stopped vehicles✓
• d.A fire blanket, a spill kit, and two wheel chocks

Federal rules require a fire extinguisher, spare fuses for vehicles that use fuses, and warning devices such as three reflective triangles. First aid kits, tow straps, spill kits, and chocks may be useful or required by a company policy, but they are not the federal emergency-equipment list.49 CFR §393.95

While checking the tractor's fifth wheel during your walkaround, what condition tells you the coupling is unsafe?

• a.There is a light coat of grease on the fifth wheel plate
• b.The release handle is in the locked position
• c.There is visible space between the upper and lower fifth wheel plates✓
• d.The locking jaws are closed around the shank of the kingpin

Any gap between the upper and lower fifth wheel plates means the trailer is not fully seated and the coupling can fail. Jaws closed around the kingpin shank, grease on the plate, and a locked release handle are all signs of a proper coupling.

You are checking steering-system play on a vehicle with a 20-inch steering wheel. How much free play is generally the maximum before the steering is considered defective?

• a.About 4 inches
• b.About 6 inches
• c.Any play at all is a defect
• d.About 2 inches✓

Roughly 10 degrees of free play, which is about 2 inches on a 20-inch wheel, is the practical limit before steering becomes hard to control. Four to six inches is excessive and would be an out-of-service condition, while a small amount of play is normal in a mechanical steering system.

You are inspecting the suspension on a trailer axle and find the main leaf of a leaf spring is broken. What is the correct action?

• a.Continue the trip but keep the load light
• b.Reduce tire pressure on that axle to compensate
• c.Continue and note the defect on tomorrow's report
• d.Place the vehicle out of service until the spring is repaired✓

A broken main leaf is an out-of-service condition because the axle can shift and the load is no longer properly supported. Lightening the load, delaying the report, or changing tire pressure does nothing to restore the suspension's ability to hold the axle in place.

Why is a leaking exhaust system a serious defect that must be corrected before driving?

• a.It prevents the transmission from shifting into high gear
• b.It automatically triggers the low-air-pressure warning
• c.It always causes the engine to stall at highway speed
• d.Exhaust gas including carbon monoxide can enter the cab and poison the driver✓

Leaking exhaust can allow carbon monoxide and heat into the cab and can ignite nearby fuel or wiring, which is why it must be repaired before operating. Exhaust leaks do not stall the engine on their own, have nothing to do with air-pressure warnings, and do not lock out the transmission.

During the applied-pressure portion of your air-brake test, what does the low-pressure warning coming on at 55 psi tell you?

• a.The system is fine because the warning came on below 60 psi
• b.The governor is set too high
• c.The spring brakes are already applied
• d.The warning device is defective because it must activate at or before 60 psi✓

The warning must activate at or before 60 psi, so a device that waits until 55 psi is out of adjustment and gives the driver too little time to react. It is not evidence of a governor problem, and spring brakes do not apply until roughly 20 to 45 psi.

During the static leak test you find air pressure dropping steadily and you can hear a hiss near the trailer air lines. What should you do?

• a.Take the vehicle out of service until the leak is repaired✓
• b.Add air with a shop line before each leg of the trip
• c.Apply the trailer hand valve to seal the leak
• d.Drive slowly to the delivery point and report it there

An audible, ongoing air leak means the system may not hold enough pressure to operate the brakes, so the vehicle must not be driven until it is repaired. Driving to a delivery point, topping off pressure, or applying a hand valve masks the problem without fixing the loss of braking capability.

You start the engine with the air tanks nearly empty and watch the gauge. On a dual air system, roughly how quickly should pressure build from 85 to 100 psi at operating rpm?

• a.Within 15 seconds
• b.Within about 45 seconds✓
• c.Within 3 minutes
• d.Within 5 seconds

A properly working dual air system should build from 85 to 100 psi in about 45 seconds at operating rpm. Five or fifteen seconds is unrealistically fast for a truck compressor, and three minutes indicates a weak compressor or a leak that must be repaired.

At what pressure should the air compressor governor normally cut out and stop pumping air?

• a.Between 120 and 140 psi✓
• b.Between 85 and 100 psi
• c.Between 150 and 170 psi
• d.Between 60 and 80 psi

The governor typically cuts out somewhere between 120 and 140 psi and cuts back in around 85 to 100 psi. Cutting out at 60 to 80 psi would leave too little reserve, and 150 to 170 psi would over-pressurize the system.

You are performing the tug test after coupling. What are you actually checking?

• a.That the landing gear is strong enough to hold the trailer
• b.That the trailer brakes release quickly enough
• c.That the electrical cord carries enough current
• d.That the fifth wheel locking jaws have fully closed around the kingpin and the trailer will not pull free✓

With the trailer brakes locked, gently pulling forward proves the coupling is holding the kingpin. The tug test says nothing about brake release timing, landing gear strength, or the electrical circuit, each of which is checked separately.

Which wheel and rim condition requires the vehicle to be taken out of service?

• a.Light surface rust on the rim
• b.A cracked rim or a wheel with missing, loose, or broken lugs✓
• c.A missing hubcap
• d.Mud packed in the wheel well

Cracked rims and missing or loose lug nuts can cause a wheel to separate from the vehicle and are out-of-service conditions. Surface rust, a missing hubcap, and packed mud are housekeeping issues rather than defects that make the wheel unsafe.

You notice oil or grease on the outside of a brake drum during your walkaround. Why does this matter?

• a.It prevents the ABS light from working
• b.It causes the drum to rust faster
• c.Contamination on the friction surfaces greatly reduces braking power✓
• d.It makes the wheel bearings spin too freely

Oil or grease on brake linings and drums destroys the friction the brake depends on, so stopping distance increases sharply and braking can become uneven. Rust, bearing speed, and the ABS lamp are unrelated to contaminated friction surfaces.

Which item is checked as part of the in-cab portion of the pre-trip inspection?

• a.Kingpin wear on the trailer
• b.Gauges, warning lights, wipers, horn, mirrors, and emergency equipment✓
• c.Slack adjuster travel at each wheel
• d.Tread depth on the drive tires

The in-cab step covers instruments, warning lamps and buzzers, wipers, horn, mirror adjustment, seat belt, and the presence of emergency equipment. Slack adjusters, the kingpin, and tire tread are all checked outside during the walkaround.

The previous driver's inspection report lists a defect that the shop has certified as repaired. What must you do before driving?

• a.Contact the previous driver to confirm
• b.Prepare a brand new report describing the old defect
• c.Review the report and sign it to acknowledge the repair or the certification that no repair was needed✓
• d.Nothing, since a mechanic already signed off

The next driver must review the prior report and sign it, confirming that the listed defect has been repaired or certified as not needing repair. Doing nothing skips a required signature, writing a new report about an old defect is not the rule, and contacting the previous driver is unnecessary.49 CFR §396.11

You are checking slack adjusters on an S-cam brake by pulling the pushrod by hand with the brakes released. What indicates the brakes are out of adjustment?

• a.The pushrod does not move at all
• b.The pushrod moves more than about one inch where it leaves the chamber✓
• c.The brake chamber is mounted upside down relative to the axle
• d.The slack adjuster is warm to the touch

More than roughly one inch of hand movement at the point the rod leaves the chamber signals brakes that need adjusting and will not develop full force. No movement is normal for a properly adjusted brake, warmth is expected after driving, and chamber orientation varies by design.

After a trip you find a small crack in the windshield directly in the driver's line of sight and a wiper blade that is torn. What is the correct assessment?

• a.Neither condition affects safety
• b.Only the wiper matters because glass damage is cosmetic
• c.Only the windshield matters because wipers are optional equipment
• d.Both are defects that affect the driver's ability to see and must be reported and repaired✓

Damaged glass in the driver's field of view and a torn wiper blade both degrade visibility, so both must be reported and corrected. Wipers are required equipment, and glass damage in the sightline is a safety defect rather than cosmetic.

Which statement best describes the driver's legal responsibility before operating a commercial vehicle?

• a.The driver must be satisfied that service brakes, parking brake, steering, lights, tires, horn, wipers, mirrors, coupling devices, wheels, and emergency equipment are in good working order✓
• b.Only the motor carrier is responsible for vehicle condition
• c.Responsibility begins only after the first 50 miles of the trip
• d.The mechanic's signature transfers responsibility away from the driver

The regulation places a personal duty on the driver to be satisfied that a specific list of components is in good working order before driving. A mechanic's signature and the carrier's own duties do not remove the driver's responsibility, and it applies from the first mile.49 CFR §392.7

You are inspecting the air lines between tractor and trailer. Which condition is acceptable?

• a.A line temporarily patched with electrical tape
• b.A hose rubbing against the frame with the outer cover worn through
• c.Glad hands sealed with rubber grommets in good condition and lines secured so they cannot chafe✓
• d.Air lines dragging on the ground behind the tractor

Air lines must be secured, free of chafing, and sealed at the glad hands with sound grommets. Worn-through covers, dragging lines, and tape patches all invite a sudden loss of air pressure while driving.

Why must you drain moisture from the air tanks or verify that the automatic drain valves are working?

• a.Water and oil in the tanks can freeze in cold weather and damage the system, reducing braking ability✓
• b.Draining is only needed on trailers, not tractors
• c.It keeps the compressor from over-charging the batteries
• d.Water increases the governor cut-out pressure

Compressed air carries moisture and oil that collect in the tanks, where they can freeze and block valves or corrode components until braking is compromised. Draining does not affect governor settings or the charging system, and it applies to tanks on every unit.

You are stopped at a roadside inspection and the officer places the vehicle out of service. What does that mean?

• a.The vehicle may not be driven until the defects that caused the order are corrected✓
• b.The driver may continue if the load is time sensitive
• c.The order applies only to the trailer, never the power unit
• d.The vehicle may be driven to the nearest terminal at reduced speed

An out-of-service order prohibits operating the vehicle until the specific defects are repaired and the order is cleared. There is no reduced-speed exception, the order can apply to any unit in the combination, and a time-sensitive load never justifies moving an unsafe vehicle.

Total stopping distance is made up of which three parts?

• a.Following distance, reaction distance, and skid distance
• b.Perception distance, reaction distance, and braking distance✓
• c.Braking distance, coasting distance, and cushion distance
• d.Sight distance, signal distance, and stopping distance

Total stopping distance equals the distance traveled while you perceive a hazard, plus the distance traveled while you move your foot to the brake, plus the distance the vehicle travels while braking. Following distance and cushion space are separate space-management ideas, and terms like coasting or signal distance are not part of the calculation.

You are traveling at 55 mph on dry pavement in a heavy vehicle. Roughly what total distance will you cover from the moment a hazard appears until you are stopped?

• a.About 1,000 feet
• b.About 60 feet
• c.About 300 feet, longer than a football field✓
• d.About 100 feet

At 55 mph perception is roughly 60 feet, reaction is roughly 60 feet, and braking adds about 170 feet or more, for a total of around 300 feet. One hundred feet or 60 feet would not even cover perception and reaction, and 1,000 feet overstates the distance on dry pavement.

If you double your speed from 20 mph to 40 mph, what happens to your braking distance?

• a.It roughly doubles
• b.It stays about the same
• c.It becomes about four times longer✓
• d.It becomes about ten times longer

Braking distance increases with the square of speed, so doubling speed multiplies braking distance by about four. Assuming it stays the same or merely doubles badly underestimates the energy the brakes must absorb, and ten times overstates it.

You are driving a 40-foot straight truck at 35 mph on a dry road. What is the minimum safe following distance?

• a.2 seconds
• b.6 seconds
• c.3 seconds
• d.4 seconds✓

Below 40 mph the rule is one second for every 10 feet of vehicle length, so a 40-foot vehicle needs 4 seconds. Two or three seconds is too little for that length, and 6 seconds would be the figure for a much longer vehicle or after adding time for higher speed.

The same 40-foot vehicle is now traveling at 55 mph on dry pavement. What following distance should you keep?

• a.4 seconds
• b.5 seconds✓
• c.3 seconds
• d.2 seconds

Above 40 mph you add one second to the length-based figure, so 4 seconds becomes 5 seconds. Keeping only 2, 3, or 4 seconds leaves too little room for the longer stopping distance at highway speed.

Rain has just begun after a long dry spell and the road surface is slick. How should you adjust your following distance and speed?

• a.Increase speed slightly to get off the wet road sooner
• b.Follow closer so the vehicle ahead clears water from your lane
• c.Keep the same following distance but brake earlier
• d.Add at least one second of following distance and reduce speed by about one third✓

On a wet road you should slow by roughly a third and add space, because traction and stopping ability are both reduced. Braking earlier alone does not create the extra cushion, and increasing speed or following closer directly increases the risk of a rear-end collision.

You are approaching a curve posted at 40 mph while driving a loaded tractor-trailer. What is the safest approach?

• a.Enter at 45 mph and coast
• b.Enter at 40 mph and brake through the curve
• c.Slow to about 10 mph below the posted speed before entering, then accelerate gently through the curve✓
• d.Brake in the middle of the curve to control speed

Posted curve speeds are set for passenger cars, so a high, heavy vehicle should be well below them and should complete braking before the curve begins. Braking inside a curve can break traction and cause a skid or rollover, and coasting through above the posted speed invites a rollover.

You are starting down a long, steep grade in a loaded truck. What is the correct braking technique?

• a.Shift into neutral and use the brakes only when needed
• b.Select a low gear before the descent, then apply the brakes firmly enough to slow about 5 mph below your safe speed, release, and repeat as speed builds back up✓
• c.Use the service brakes continuously and downshift only at the bottom
• d.Ride the brakes lightly the whole way down to hold a constant speed

Snub braking, combined with a gear selected before the descent, lets the brakes cool between applications and keeps the engine helping to hold speed. Riding or continuously applying the brakes overheats them and causes brake fade, and coasting in neutral removes engine braking entirely and is illegal in many states.

Which factors determine the safe speed for descending a mountain grade?

• a.Only the size of the engine
• b.Only the type of brakes installed
• c.Total vehicle weight, length and steepness of the grade, road and weather conditions, and the amount of traffic✓
• d.Only the posted speed limit

Safe descent speed depends on how much weight the brakes must control, how long and steep the grade is, and the conditions around you. A posted limit is a maximum for ideal conditions, and neither engine size nor brake type alone determines a safe speed.

How far ahead should a commercial driver normally be looking while driving?

• a.As far as the headlights reach at all times
• b.Just past the front bumper
• c.About 5 seconds ahead
• d.About 12 to 15 seconds ahead, which is roughly a quarter mile at highway speed✓

Looking 12 to 15 seconds ahead gives you time to see and respond to developing hazards instead of reacting at the last moment. Looking just past the bumper or only 5 seconds ahead is far too short, and headlight range is a night-driving limit rather than a general rule.

How often should you check your mirrors while driving?

• a.Only when changing lanes
• b.Only when another vehicle sounds its horn
• c.Once every mile
• d.Regularly, about every 5 to 8 seconds, and before any lane change, turn, or speed change✓

Frequent scanning every few seconds keeps you aware of traffic entering your blind spots and of your own vehicle and cargo. Checking only at lane changes, at fixed mileage, or after a horn means you learn about hazards too late.

Where are the largest blind spots on a tractor-trailer?

• a.Only behind the trailer
• b.Directly ahead of the bumper and above the trailer
• c.Immediately in front of the cab, along both sides especially the right, and directly behind the trailer✓
• d.Only on the driver's side

Heavy vehicles have no-zones in front of the cab, along both sides with the right side much larger, and directly behind the trailer. Saying the blind spot is only behind or only on the left ignores the right-side no-zone where most sideswipe crashes occur.

You are driving at night on an unlit two-lane road. Why should you keep your speed low enough to stop within the distance your headlights illuminate?

• a.Because tire traction is always lower at night
• b.Because if you cannot stop within the lighted distance you are overdriving your headlights and cannot react to a hazard in time✓
• c.Because engine braking works poorly at night
• d.Because high beams are illegal on two-lane roads

Low beams light roughly 250 feet and high beams roughly 350 to 500 feet, so speed must be low enough to stop inside that distance. High beams are legal when no oncoming traffic is present, engine braking works the same at night, and traction depends on the surface rather than the hour.

You run into dense fog on the highway. What is the best course of action?

• a.Slow down, use low beams and fog lights, and if visibility is very poor pull completely off the road and turn on your four-way flashers✓
• b.Turn on your high beams so you can see farther
• c.Speed up to get through the fog quickly
• d.Follow closely behind another vehicle's tail lights

Low beams cut glare in fog while high beams reflect back and reduce visibility further, and getting fully off the roadway is safest when you can barely see. Speeding up and tailgating another vehicle's lights are two of the most common causes of fog chain-reaction crashes.

You have just driven through deep standing water and your brakes feel weak. What should you do?

• a.Drive slowly while applying light pressure to the brakes to generate heat and dry them out✓
• b.Stop immediately and wait for the brakes to air dry
• c.Pump the brake pedal rapidly while accelerating
• d.Set the parking brake while rolling

Light steady pressure while moving slowly creates the friction heat that dries wet linings and restores braking. Waiting can leave the brakes wet, rapid pumping while accelerating does not create sustained heat, and applying the parking brake while rolling can lock the drive wheels.

At what speed can hydroplaning begin when there is a large amount of water on the road?

• a.Only above 70 mph
• b.Only when tires are over-inflated
• c.Only above 55 mph
• d.As low as 30 mph✓

With enough standing water, hydroplaning can start around 30 mph, and low tread depth or under-inflation makes it more likely. Believing it only happens at 55 or 70 mph leads drivers to keep unsafe speeds in heavy rain, and it is under-inflation rather than over-inflation that raises the risk.

Your drive wheels begin to skid when you brake hard on a slick surface. What is the correct recovery?

• a.Brake harder to force the wheels to grip
• b.Accelerate to pull the trailer straight
• c.Release the brakes to let the wheels roll again, push in the clutch, and steer in the direction you want the vehicle to go✓
• d.Set the parking brake to straighten the vehicle

A locked wheel cannot steer, so you must let it turn again before steering will do anything, and countersteering brings the rear back in line. Braking harder deepens the skid, the parking brake locks the drive axle, and accelerating in a skid worsens the loss of traction.

You are steering into a corner and the front end pushes straight ahead instead of turning. What is the most likely cause of this front-wheel skid?

• a.The trailer brakes are dragging
• b.Driving too fast for conditions, worn or under-inflated front tires, or a very light load on the front axle✓
• c.The steering wheel is turned too little
• d.The engine brake is engaged

Front-wheel skids come from asking more of the steer tires than the available traction allows, usually because of excess speed, poor tire condition, or too little weight on the front axle. Dragging trailer brakes and an engaged engine brake affect the rear, and turning the wheel more only increases the skid.

You are driving a placarded hazardous materials load and approach an unguarded railroad crossing. What must you do?

• a.Sound the horn and cross at normal speed
• b.Stop directly on the first rail to get the best view
• c.Proceed without stopping if no train is visible
• d.Stop no closer than 15 feet and no farther than 50 feet from the nearest rail, look and listen, then cross without shifting gears✓

Placarded hazmat vehicles, most buses, and cargo tanks must stop between 15 and 50 feet from the nearest rail, check both directions, and cross in a gear that will not require shifting. Rolling through, relying on the horn, or stopping on the tracks all defeat the purpose of the required stop.49 CFR §392.10

Why should you never start across a railroad crossing unless you are certain you can clear it completely?

• a.Because the crossing surface damages tires
• b.Because crossing gates close automatically after 10 seconds
• c.Because state law requires a permit
• d.Because a long, heavy vehicle can become trapped on the tracks with no room to move forward or back✓

Traffic backed up on the far side can leave a long vehicle stopped on the rails with nowhere to go, so you must have room on the other side before you start. Gates do not operate on a fixed 10-second timer, no permit is required for a normal crossing, and tire damage is not the reason for the rule.

You are entering a highway work zone with reduced lanes and workers present. What is the correct driving behavior?

• a.Change lanes as often as needed to keep moving
• b.Use the shoulder to bypass slow traffic
• c.Slow to the posted work-zone speed, increase following distance, avoid unnecessary lane changes, and watch for workers and equipment✓
• d.Maintain highway speed until you see a worker in the lane

Work zones combine narrowed lanes, sudden stops, and people on foot, so lower speed and extra space are essential, and fines are often doubled. Maintaining highway speed, weaving between lanes, and using the shoulder all increase the risk to workers and to you.

You are about to change lanes on a busy interstate. What is the correct communicating procedure?

• a.Signal only if another vehicle is close behind
• b.Change lanes first and signal once you are established
• c.Signal early, check mirrors and the blind spot, change lanes gradually, and cancel the signal after completing the move✓
• d.Flash your headlights instead of signaling

Signaling early gives other drivers time to react, and canceling afterward prevents confusion about your intentions. Signaling after the move, substituting headlight flashes, or signaling only sometimes leaves other drivers guessing.

You must stop on the shoulder of a divided highway because of a mechanical problem. Where do you place your warning devices?

• a.One within 10 feet of the rear, one about 100 feet back, and one about 200 feet back toward approaching traffic✓
• b.One at 50 feet and two at 500 feet
• c.All three within 10 feet of the vehicle
• d.Only one, directly behind the vehicle

On a divided or one-way roadway the triangles go at roughly 10, 100, and 200 feet behind the vehicle facing approaching traffic, and they must be placed within 10 minutes. Bunching them at the vehicle, using only one, or the 50 and 500 foot spacing does not give approaching drivers proper warning.

You are driving an empty flatbed trailer in strong crosswinds on an open stretch of highway. What is the greatest concern?

• a.Fuel consumption will drop
• b.The engine will overheat
• c.The air brakes will lose pressure faster
• d.The light trailer can be pushed sideways or even blown over, so speed must be reduced✓

An empty or lightly loaded high-sided trailer has little weight to resist wind force, so a strong gust can push it out of the lane or tip it. Wind does not cause overheating or air loss, and fuel savings are irrelevant to the safety issue.

Which surface is most likely to be icy first when temperatures drop toward freezing?

• a.The center of an urban intersection
• b.Bridges, overpasses, and shaded areas✓
• c.A long straight stretch of dry asphalt
• d.A recently paved uphill lane

Bridges and overpasses lose heat from both the top and the underside and freeze before the surrounding road, and shaded spots stay cold longer. Sun-exposed straight roads, busy intersections, and fresh pavement generally retain heat longer.

You are following a car at a safe distance when another driver cuts into the gap in front of you. What should you do?

• a.Speed up and stay close so no one else can merge
• b.Sound your horn continuously
• c.Flash your high beams to make the driver move over
• d.Ease off the accelerator and drop back to re-establish a safe following distance✓

The only useful response is to rebuild the space cushion you need to stop safely. Flashing lights, tailgating, and prolonged horn use escalate the situation without restoring the stopping distance you just lost.

You are driving slower than the flow of traffic because of a heavy load on a long upgrade. What is the correct action?

• a.Stay in the right lane and turn on your four-way flashers to warn faster traffic✓
• b.Speed up beyond a safe speed to match traffic
• c.Drive on the shoulder
• d.Move to the left lane so others can pass on the right

Staying right and using hazard flashers warns approaching drivers that you are moving well below traffic speed. Blocking the left lane, driving on the shoulder, and forcing an unsafe speed all create additional hazards.

Why does an empty truck often take longer to stop than the same truck when loaded?

• a.The brakes are disconnected when empty
• b.Empty trucks always travel at higher speeds
• c.With less weight pressing the tires down there is less traction, and the stiff suspension and brakes sized for a full load cause wheels to lock up more easily✓
• d.Empty trucks have smaller brake chambers

Braking systems and suspensions on heavy vehicles are designed for a loaded weight, so an empty vehicle has reduced traction and lock-up occurs sooner. Speed is a driver choice, brakes are never disconnected, and chamber size does not change with the load.

A driver behind you is tailgating your trailer on a two-lane road. What is the safest response?

• a.Increase your own following distance, stay steady, avoid sudden moves, and make it easy for the driver to pass✓
• b.Turn on your hazard lights and stop in the lane
• c.Speed up until the driver falls back
• d.Brake sharply to send a message

Extra space ahead gives you room to slow gradually instead of braking hard in front of a tailgater. Brake-checking, racing away, and stopping in a travel lane all raise the chance of the rear-end collision you are trying to avoid.

On a mountain grade you see a sign for a runaway vehicle ramp ahead. What is its purpose?

• a.It is a parking area for chaining up in winter
• b.It is a mandatory rest stop for descending vehicles
• c.It is a required weigh station for loaded trucks
• d.It is an escape route designed to stop a vehicle that has lost braking ability✓

Escape ramps use gravel beds or upgrades to stop a vehicle whose brakes have faded or failed, and using one is far better than continuing downhill. They are not weigh stations, chain-up areas, or required rest stops.

You are driving in heavy snow and your windshield keeps icing over despite the wipers. What should you do?

• a.Open the side window and steer by watching the fog line
• b.Reach out the window and clear the glass while driving slowly
• c.Pull off the road in a safe place, clear the ice, and check that the defroster and wipers work before continuing✓
• d.Follow closely behind a plow so its spray keeps the glass clear

Driving without a clear view is unsafe at any speed, so the correct response is to stop somewhere safe and restore visibility. Clearing glass while moving, tailgating a plow, and steering by the fog line all substitute for the vision you no longer have.

Why should you manage space to the sides as well as ahead of your vehicle?

• a.A heavy vehicle needs room to maneuver, and staying centered keeps you from being trapped when another driver drifts or a hazard appears✓
• b.Side space only matters in city driving
• c.Wide vehicles are exempt from lane position rules
• d.Side clearance is regulated only for oversize loads

Keeping a cushion on both sides preserves an escape path when a hazard develops and prevents being boxed in by other traffic. Side space matters at highway speed as much as in town, and no exemption relieves a wide vehicle of staying in its lane.

Which sequence describes double clutching to shift into a higher gear?

• a.Accelerate hard, shift without the clutch, then brake
• b.Release the accelerator, push in the clutch and shift to neutral, release the clutch, let engine and gear speeds drop to the range for the next gear, push in the clutch and shift to the higher gear, release the clutch and accelerate✓
• c.Shift to neutral, coast until the vehicle slows, then select any gear
• d.Push in the clutch once, shift directly to the higher gear, and release the clutch

Double clutching passes through neutral with the clutch released so engine and transmission speeds can match before the next gear is selected. Single clutching, floating gears without matching speeds, and coasting in neutral all grind gears or leave the vehicle without power control.

When downshifting, what do you do differently compared with upshifting?

• a.While in neutral with the clutch released, you press the accelerator to raise engine rpm before selecting the lower gear✓
• b.You apply the service brakes throughout the shift
• c.You hold the clutch down through the whole shift
• d.You skip neutral entirely

A lower gear turns faster at the same road speed, so engine speed must be increased in neutral to match it. Skipping neutral, riding the clutch, or braking through the shift prevents the speeds from matching and can damage the transmission.

You are approaching a steep downgrade in a truck with a manual transmission. When should you select your gear?

• a.Before you start down the hill, while you still have engine and road speed to shift✓
• b.Halfway down, once you can judge the grade
• c.Only if the brakes begin to fade
• d.At the bottom, after the vehicle slows

Once you are descending it may be impossible to shift into a lower gear, leaving you stuck in neutral with no engine braking. Waiting until partway down, until the bottom, or until the brakes fade all remove the option to select a safe gear.

How do you know when to shift using engine speed?

• a.Shift at the same road speed in every gear
• b.Shift whenever the vehicle feels slow
• c.Learn the operating rpm range for your engine and shift up when the tachometer reaches the top of that range✓
• d.Shift only when the engine stalls

Each engine has a recommended rpm operating range, and the tachometer tells you when the engine has reached the point to shift. Guessing by feel, using a fixed road speed for all gears, or waiting for a stall wastes fuel and can over-rev or lug the engine.

You need to back into a tight dock space and you have a choice of approach. What should you do?

• a.Back at normal forward speed to keep momentum
• b.Back toward the driver's side so you can see the trailer and the space through the side window✓
• c.Back toward the blind side because it is a shorter turn
• d.Rely only on the passenger-side mirror

Driver-side backing lets you look directly out the window and see the rear of the trailer, which is why it is the preferred method. Blind-side backing hides the danger zone, backing fast removes reaction time, and using a single mirror leaves half the area unseen.

What does the safe-backing practice known as GOAL stand for and require?

• a.Gear Out And Lock, meaning you lock the differential
• b.Go Only At Low speed, meaning speed is the only concern
• c.Gauge Overhead And Left, meaning you check only overhead clearance
• d.Get Out And Look, meaning you walk back to inspect the path and clearances before and during backing✓

Getting out and physically checking the path is the single most reliable way to avoid striking objects you cannot see from the seat. The other expansions are invented and none of them replaces actually inspecting the area behind the vehicle.

You are backing a trailer and it begins to drift off your intended line. What is the correct correction?

• a.Set the parking brake and start over from the dock
• b.Stop, correct with small steering movements or pull forward to reposition, and back slowly using both mirrors✓
• c.Continue backing and hope it straightens
• d.Turn the steering wheel sharply and keep backing quickly

Small corrections made early keep the trailer on line, and pulling forward to reset is always acceptable when the angle gets away from you. Continuing blindly, oversteering at speed, or abandoning the maneuver mid-position leads to a jackknife or a collision.

You are making a tight right turn at an intersection in a tractor-trailer. What is the correct technique?

• a.Straddle both lanes for the entire turn
• b.Signal left, then turn right
• c.Keep the rear of the vehicle close to the curb, turn wide as you complete the turn rather than before it, and do not let a vehicle squeeze in on your right✓
• d.Swing wide to the left before turning so the trailer clears

Turning wide at the end keeps the trailer from riding over the curb while preventing another driver from slipping into the gap on your right. Swinging left first invites a vehicle beside you, a left signal misleads other drivers, and straddling lanes for the whole turn blocks traffic unnecessarily.

What is off-tracking, and why does it matter in turns?

• a.The trailer rides a wider path than the tractor, so you must stay left
• b.The trailer brakes apply before the tractor brakes
• c.The vehicle drifts backward on an upgrade
• d.The rear wheels follow a shorter path than the front wheels, so the trailer can cut across curbs, poles, or an adjacent lane✓

Because the rear wheels track inside the path of the steer axle, the longer the vehicle the more the rear cuts the corner. Trailers do not swing wider than the tractor in a turn, and rollback and brake timing are separate issues.

You are coupling a tractor to a trailer. Which step comes immediately before backing under the trailer?

• a.Perform the tug test
• b.Raise the landing gear fully
• c.Remove the wheel chocks
• d.Connect the air lines, supply air to the trailer, and make sure the trailer brakes are locked✓

Charging the trailer air system and locking its brakes keeps the trailer from rolling as the fifth wheel slides under the apron. Raising the landing gear, removing chocks, and the tug test all come after the coupling is made.

Before backing under a trailer, how should the trailer height be set?

• a.Slightly lower than the center of the fifth wheel so the trailer is lifted a little as the tractor backs under✓
• b.As high as the landing gear will go
• c.High enough that the fifth wheel passes underneath without touching
• d.Exactly level with the top of the fifth wheel

A trailer set slightly low is raised as the tractor backs under, which ensures the kingpin engages the jaws properly. A trailer that is too high lets the tractor slide under without coupling or strikes the nose, and exactly level or fully raised risks a missed or damaged coupling.

You are uncoupling a trailer in a yard. Which sequence is correct?

• a.Disconnect the air lines first, then pull forward, then lower the landing gear
• b.Pull the fifth wheel release, then lower the landing gear, then chock the wheels
• c.Ease pressure on the locking jaws, chock the trailer wheels, lower the landing gear until it takes the weight, disconnect the air and electrical lines and secure them, pull the release handle, and pull the tractor partially clear before checking✓
• d.Lower the landing gear, pull completely clear, then disconnect the lines

Taking pressure off the jaws, securing the trailer, setting the landing gear, and only then releasing and easing forward keeps the trailer supported at every step. The other sequences release the coupling or the lines before the trailer is supported, which can drop the trailer or tear the air lines apart.

After uncoupling, you notice the landing gear crank handle is left extended. Why must it be secured?

• a.An unsecured handle can catch on a passing vehicle or on the tractor and cause injury or damage✓
• b.It affects the trailer air pressure
• c.It changes the axle weight distribution
• d.It voids the inspection report

A crank handle left hanging is a physical hazard that can strike people or equipment moving nearby. It has no effect on air pressure, weight distribution, or the validity of an inspection report.

You are parking on a slight grade and will leave the vehicle. What should you do?

• a.Leave the engine running so the air system stays charged
• b.Rely on the service brakes alone
• c.Leave the transmission in a low gear with the brakes released
• d.Shut the engine off, apply the parking brakes, and chock the wheels if the vehicle may roll✓

Parking brakes plus chocks are what hold a heavy vehicle on a grade once the driver leaves. Service brakes bleed off as air pressure drops, and leaving the engine running or the brakes released allows the vehicle to move.

You are on a slick, snow-covered road descending a grade. What should you do with the engine brake or retarder?

• a.Use it only in combination with the trailer hand valve
• b.Turn it off, because a retarder can cause the drive wheels to lose traction and skid on a slippery surface✓
• c.Cycle it on and off every few seconds
• d.Set it to the highest setting for maximum control

Retarders act on the drive wheels, and on ice or packed snow that braking force can break traction and start a jackknife. Higher settings and rapid cycling make the problem worse, and the trailer hand valve should not be used as a speed-control device on a grade.

You are stopped on an upgrade in a manual-transmission truck and need to start moving without rolling back. What is the correct technique?

• a.Partially engage the clutch until you feel the vehicle try to move, then release the parking brake while adding throttle✓
• b.Start in the highest gear available
• c.Rev the engine to maximum and drop the clutch
• d.Release the parking brake first, then find the friction point

Holding the vehicle with the parking brake until the clutch takes hold prevents rollback into whatever is behind you. Releasing the brake first causes rollback, dumping the clutch at high rpm shocks the driveline, and starting in a high gear stalls the engine.

How should you hold the steering wheel when driving a heavy vehicle?

• a.Firmly with both hands on opposite sides of the wheel✓
• b.With one hand at the top of the wheel
• c.With both hands together at the bottom
• d.With the wrist hooked over the top spoke

Both hands on opposite sides give the leverage and control needed if a tire blows or you hit a rut. One-handed, hooked-wrist, and hands-together grips can all be torn loose by a sudden jolt through the steering.

What is the correct way to make a normal stop in a vehicle with air brakes?

• a.Push the brake pedal down steadily and control the pressure so the vehicle comes to a smooth stop✓
• b.Pull the trailer hand valve first and then use the pedal
• c.Stab the pedal down and release repeatedly
• d.Shift to neutral and let the vehicle coast to a stop

Steady, controlled pedal pressure produces a smooth stop and keeps the vehicle in line. Stab braking is an emergency technique, the trailer hand valve alone can cause a trailer skid, and coasting in neutral removes engine braking and control.

Why should you avoid coasting in neutral while driving a commercial vehicle?

• a.It wears out the clutch pedal spring
• b.You lose engine braking and the ability to accelerate out of a hazard, and it is illegal in many states✓
• c.It causes the tachometer to read incorrectly
• d.It automatically disables the ABS

In neutral the engine no longer helps control speed and you cannot power away from a developing hazard, which is why most states prohibit it. Clutch springs, tachometer accuracy, and ABS operation are unrelated to being in neutral.

You need to pull into a truck stop space at night and only a blind-side space is open. What is the safest practice?

• a.Back in using the mirrors alone without stopping
• b.Get out and look, walk the path, use a spotter if one is available, and back very slowly with frequent stops to re-check✓
• c.Back in quickly before other traffic arrives
• d.Park in the driving lane instead

A blind-side maneuver hides the danger area, so walking the path and using a helper or repeated checks is the only safe approach. Rushing, relying only on mirrors, and blocking a driving lane each create a greater hazard.

What happens if you turn too sharply while backing a tractor-trailer?

• a.The fifth wheel unlocks
• b.The steering axle lifts off the ground
• c.The trailer can jackknife against the tractor and damage both units✓
• d.The trailer brakes lock automatically

Excessive angle between tractor and trailer during backing folds the units together and can crush the cab, fenders, or air lines. Trailer brakes do not lock on their own, the steer axle stays down, and the fifth wheel does not unlock from a sharp angle.

Why should you check the trailer height and the position of the fifth wheel jaws visually after coupling, even after a successful tug test?

• a.Visual checks are only needed on flatbed trailers
• b.The tug test only checks the electrical connection
• c.The jaws cannot be seen from outside the vehicle
• d.A high hitch can appear locked while the kingpin sits on top of the closed jaws, which can pull apart in traffic✓

A high hitch can leave the kingpin resting above the jaws so the coupling looks secure but is not, which is why the manual requires looking under the trailer with a flashlight. Visual checks apply to all trailer types, the tug test is a mechanical check, and the jaws are visible from beneath the coupling.

A car pulls out directly in front of you and there is not enough distance to stop. What is generally the best response?

• a.Downshift and hope the gap clears
• b.Sound the horn and maintain speed
• c.Brake as hard as possible and hold the pedal down
• d.Steer around the hazard if there is an escape path, because a vehicle can change direction faster than it can stop✓

Stopping distance grows with the square of speed, but the time needed to steer around an obstacle changes very little, so an evasive steer is often the only option that works. Locking the brakes destroys steering control, the horn does not shorten the closing distance, and downshifting is far too slow to help.

You are traveling at highway speed when a front tire blows out. What should you do first?

• a.Brake hard immediately
• b.Accelerate to regain control
• c.Hold the steering wheel firmly, stay off the brake, and let the vehicle slow on its own before easing to the shoulder✓
• d.Steer sharply onto the shoulder

Braking on a blown tire pulls the vehicle sharply toward the failed side, so you must keep it straight and let it slow before braking gently and pulling off. Sharp steering can roll the vehicle, and accelerating adds energy to an already unstable situation.

How can you tell that a tire has failed if you did not hear the blowout?

• a.The fuel gauge drops rapidly
• b.The air pressure gauge reads zero
• c.A thumping or vibration, a sudden change in steering feel, or the rear of the vehicle fishtailing✓
• d.The engine loses power

Vibration, a pull in the steering when a front tire fails, or a fishtailing rear when a rear tire fails are the usual clues. Tire failure does not affect fuel level, brake system air pressure, or engine power.

Your right wheels drop off the pavement onto a soft shoulder at 55 mph. What is the correct recovery?

• a.Steer back onto the pavement while maintaining speed
• b.Keep a firm grip, stay off the brake and take your foot off the accelerator, let the vehicle slow, then turn back onto the pavement sharply at low speed✓
• c.Accelerate to power back onto the road
• d.Brake hard and steer left immediately

Trying to climb back onto the pavement at speed can throw the vehicle across the road or into a rollover, so you slow first and then make a deliberate sharp return. Hard braking on a soft shoulder can cause a skid, and accelerating increases the speed at which you re-enter the lane.

Your air brakes fail on a downgrade and the low-pressure warning is on. What is your best course of action?

• a.Downshift to use engine braking, look for an escape ramp or an uphill escape route, and use the parking brake or a soft-shoulder route as a last resort✓
• b.Pump the brake pedal rapidly to rebuild pressure
• c.Shut off the engine to stop the vehicle
• d.Shift to neutral so the vehicle rolls more freely

Engine braking and an escape ramp are the reliable tools once the service brakes are gone, and speed must be controlled before it becomes uncontrollable. Pumping air brakes wastes remaining pressure, neutral increases speed, and shutting off the engine removes power steering and engine braking together.

Which type of fire extinguisher should you use on an electrical fire in the cab?

• a.A pressurized garden hose
• b.Any extinguisher, as long as it is full
• c.A water extinguisher
• d.A B:C rated extinguisher such as dry chemical or carbon dioxide✓

Electrical fires are Class C, so the agent must be non-conductive, which is why a B:C or A:B:C rated dry chemical or carbon dioxide unit is required. Water conducts electricity and can electrocute the user or spread the fire, and choosing an extinguisher by fullness alone ignores the class rating.

A grease or fuel fire starts near the engine. Why must you never use water on it?

• a.Water damages the paint
• b.Water freezes on hot metal
• c.Water is too heavy to carry
• d.Water spreads burning liquid instead of putting it out✓

Burning liquids float on water, so a stream of water scatters the fire over a larger area. Weight, freezing, and paint damage are irrelevant compared with the danger of spreading a Class B fire.

You are using a fire extinguisher on a small cargo fire. What is the correct technique?

• a.Stay upwind, position yourself about 6 to 10 feet away, pull the pin, aim at the base of the fire, and sweep side to side✓
• b.Empty the extinguisher into the smoke above the fire
• c.Stand as close as possible and aim at the top of the flames
• d.Approach from downwind so the wind carries the agent in

Aiming at the base attacks the fuel source, and staying upwind and back keeps you clear of heat and fumes. Standing too close, spraying smoke, or approaching from downwind exposes you to the fire and wastes the extinguisher's limited charge.

What is the minimum fire extinguisher rating required on a vehicle transporting hazardous materials that requires placards?

• a.No extinguisher is required if the load is non-flammable
• b.Two 2 B:C extinguishers
• c.A single extinguisher with a rating of at least 10 B:C✓
• d.A single 5 B:C extinguisher

Placarded hazardous materials vehicles must carry an extinguisher rated at least 10 B:C, while other commercial vehicles need at least a 5 B:C or two units rated 4 B:C each. Smaller units do not meet the hazmat standard, and every commercial vehicle needs an extinguisher regardless of the cargo.49 CFR §393.95

You are the first vehicle at the scene of a crash on a rural highway. What is the correct order of priorities?

• a.Take photographs first for the insurance claim
• b.Move all injured people off the roadway immediately, then call for help
• c.Leave the scene to find a phone with better signal
• d.Protect the area so no further crashes occur, notify authorities, then care for the injured✓

Preventing a second collision protects both you and the people already involved, and emergency services are needed before hands-on care. Moving injured people risks worsening spinal injuries unless fire or another danger is present, and photographs or leaving the scene delay the response.

You have just left the shipper with a secured load. When must you first re-inspect the cargo and its securement?

• a.Within the first 50 miles of the trip✓
• b.After 500 miles
• c.Only if the load shifts noticeably
• d.Only at the destination

The rule requires an inspection within the first 50 miles, then a re-examination every 150 miles or every 3 hours of driving, whichever comes first. Waiting until the destination, 500 miles, or a noticeable shift means the securement has already failed.49 CFR §392.9

What is the minimum aggregate working load limit for the tiedowns securing a piece of cargo?

• a.At least 50 percent of the weight of the cargo being secured✓
• b.There is no numeric requirement
• c.100 percent of the weight of the cargo
• d.25 percent of the weight of the cargo

The combined working load limit of all tiedowns must equal at least half the weight of the article being secured. Twenty-five percent is below the standard, requiring 100 percent overstates the rule, and the requirement is clearly numeric.49 CFR §393.106

You are securing a single 12-foot pipe weighing 1,800 pounds on a flatbed. How many tiedowns are required at minimum?

• a.Two tiedowns
• b.Three tiedowns✓
• c.One tiedown
• d.Four tiedowns

An article longer than 10 feet needs two tiedowns for the first 10 feet plus one more for each additional 10 feet or fraction, so a 12-foot article needs three. One tiedown is only allowed for articles 5 feet or shorter and 1,100 pounds or less, and four exceeds the minimum for this length.49 CFR §393.110

Your load is stacked high in a van trailer with the heaviest cases on top. Why is this dangerous?

• a.It makes the trailer harder to unload
• b.It causes the trailer brakes to overheat
• c.A high center of gravity makes the vehicle much more likely to roll over in a curve or in a sudden maneuver✓
• d.It increases fuel consumption

Heavy weight placed high raises the center of gravity, and rollover risk climbs sharply in curves, on ramps, and during evasive steering. Unloading effort, fuel use, and brake temperature are minor compared with the stability problem.

What is the maximum gross vehicle weight generally allowed on the Interstate highway system without a special permit?

• a.60,000 pounds
• b.100,000 pounds
• c.70,000 pounds
• d.80,000 pounds✓

The federal limit is 80,000 pounds gross, with 20,000 pounds on a single axle and 34,000 pounds on a tandem axle set, subject to the bridge formula. Sixty and seventy thousand are below the legal maximum, and 100,000 pounds requires a permit.

You are scaled at 21,000 pounds on the steer axle and 33,000 pounds on the drive tandem. What is the problem?

• a.The drive tandem exceeds the tandem limit
• b.Nothing is wrong because the gross weight is legal
• c.Both axle groups are over the limit
• d.The single steer axle exceeds the 20,000 pound federal limit and weight must be shifted✓

A single axle is limited to 20,000 pounds, so 21,000 is overweight even though the tandem at 33,000 is under the 34,000 pound limit. A legal gross weight does not excuse an overloaded individual axle, and only the steer axle is over here.

You are hauling a placarded load of flammable liquid. Where must the shipping papers be kept while you are driving?

• a.In the sleeper berth
• b.Locked in the trailer with the cargo
• c.Within the driver's immediate reach while the seat belt is fastened, and clearly visible or in a pouch on the driver's door✓
• d.Emailed to the carrier is sufficient

Emergency responders must be able to find the papers quickly, so they must be within reach and identifiable from the driver's side. Papers in the trailer, in a sleeper, or only in electronic form at the office are unavailable to responders at the scene.

What is the primary purpose of hazardous materials placards on a commercial vehicle?

• a.To warn the public and emergency responders of the class of hazard on board✓
• b.To indicate the value of the cargo
• c.To identify the shipper and consignee
• d.To show the vehicle's insurance coverage

Placards communicate the hazard class so responders can select the correct tactics before approaching the vehicle. They do not identify the parties to the shipment, the cargo value, or the insurance.

A tire on your trailer catches fire at a rest area and you have a 10 B:C extinguisher. What is the realistic limitation you must plan for?

• a.The extinguisher will smother the tire fire in a few seconds
• b.A burning tire holds heat deep inside and usually needs large amounts of water, so the extinguisher may only slow it while you keep people away and call the fire department✓
• c.Dry chemical is prohibited for use near tires
• d.Tire fires go out on their own once the vehicle stops

Tires reignite because the fire burns inside the casing where a dry chemical agent cannot reach, so the priority is evacuation and calling for help. Tire fires do not self-extinguish, and dry chemical is not prohibited, it is simply not sufficient.

You pull into a rest area and smell fuel and see smoke from under the hood. What should you do?

• a.Continue driving to the nearest repair shop
• b.Shut off the engine, get yourself and any passengers away from the vehicle, and use the extinguisher only if the fire is small and you can do so safely✓
• c.Spray water on the engine compartment
• d.Open the hood fully to see the source

Cutting the fuel and ignition source and keeping people clear are the first priorities, and extinguishers are only for small, contained fires. Opening the hood feeds oxygen to the fire, driving fans the flames, and water on a fuel fire spreads it.

After taking 10 consecutive hours off duty, what is the maximum number of hours a property-carrying driver may drive?

• a.14 hours
• b.11 hours✓
• c.10 hours
• d.12 hours

A property-carrying driver may drive up to 11 hours after 10 consecutive hours off duty. The 14-hour figure is the on-duty window inside which that driving must be completed, and 10 and 12 hours are not the driving limit.49 CFR §395.3

You came on duty at 6:00 a.m. after 10 hours off. Ignoring any exceptions, what is the latest time you may still be driving?

• a.10:00 p.m.
• b.6:00 p.m.
• c.5:00 p.m.
• d.8:00 p.m.✓

The 14-hour window runs from the moment you come on duty, so driving must end by 8:00 p.m., and off-duty breaks do not extend it. Ending at 5:00 or 6:00 p.m. is earlier than required, and 10:00 p.m. is four hours past the limit.49 CFR §395.3

When must a property-carrying driver take the required 30-minute break?

• a.Every 2 hours of driving
• b.After 10 hours on duty
• c.Before driving more than 8 cumulative hours without at least a 30-minute interruption of driving time✓
• d.After 4 hours on duty

The rule triggers on 8 cumulative hours of driving time and can be satisfied by any 30 consecutive minutes not spent driving. It is not tied to 4 or 10 hours on duty, and there is no requirement to break every 2 hours.49 CFR §395.3

Your carrier operates every day of the week. Which on-duty limit applies to you?

• a.70 hours in any 8 consecutive days✓
• b.60 hours in any 7 consecutive days
• c.80 hours in any 8 consecutive days
• d.50 hours in any 6 consecutive days

Carriers operating seven days a week use the 70-hour, 8-day limit, while the 60-hour, 7-day limit applies to carriers that do not operate every day. The 50-hour and 80-hour figures are not federal limits.49 CFR §395.3

You have reached your 70-hour limit. How can you reset your available hours under the restart provision?

• a.Take 34 or more consecutive hours off duty✓
• b.Take two separate 12-hour breaks
• c.Wait until the start of the next calendar month
• d.Take 24 consecutive hours off duty

The optional restart requires at least 34 consecutive hours off duty, after which the 60 or 70-hour count begins again. A 24-hour break, split breaks, and calendar changes do not reset the weekly total.49 CFR §395.3

You encounter unexpected snow that was not forecast when you dispatched, which slows your trip badly. What relief does the adverse driving conditions exception provide?

• a.It waives the requirement to keep records for that day
• b.Up to 2 additional hours of driving time and 2 additional hours of the 14-hour window to complete the run or reach a safe place✓
• c.Unlimited driving time until the load is delivered
• d.Four additional hours of driving time

The exception adds up to two hours of driving time and extends the driving window by the same two hours when conditions could not have been known before dispatch. It is not unlimited, is not four hours, and never removes the duty to record hours.49 CFR §395.1

What is the purpose of an electronic logging device on a commercial motor vehicle?

• a.To replace the requirement to keep any supporting documents
• b.To measure axle weights while driving
• c.To automatically record driving time by connecting to the engine so hours-of-service records are accurate✓
• d.To track fuel purchases for tax reporting only

An ELD synchronizes with the engine to capture driving time automatically, which is why it replaced most paper logs. Fuel tax tracking and weight measurement are separate systems, and drivers must still retain supporting documents.49 CFR §395.8

What blood alcohol concentration makes it unlawful for a CDL holder to operate a commercial motor vehicle?

• a.0.08 or higher
• b.0.02 or higher
• c.0.10 or higher
• d.0.04 or higher✓

The commercial limit is 0.04, half the 0.08 limit that applies to most non-commercial drivers. A driver found at 0.04 or above, or with any detectable alcohol, is placed out of service for 24 hours.49 CFR §392.5

You are stopped at a roadside inspection and test at 0.02 blood alcohol concentration. What happens?

• a.Your CDL is revoked permanently on the spot
• b.Nothing, because you are below 0.04
• c.You are cited but may continue driving
• d.You are placed out of service for 24 hours because any detectable alcohol prohibits operation✓

Having any measured alcohol concentration while on duty triggers a 24-hour out-of-service order even below the 0.04 threshold that carries heavier penalties. Continuing to drive is prohibited, and a permanent revocation is not the immediate roadside consequence.49 CFR §392.5

A CDL holder refuses to submit to required alcohol testing after a crash. What is the consequence?

• a.Disqualification for at least one year, the same as a first conviction for driving under the influence✓
• b.A written warning only
• c.A 30-day suspension
• d.A fine with no effect on the license

Refusal is treated exactly like a positive test, resulting in disqualification for at least one year, or three years if the driver was transporting placarded hazardous materials. Warnings, fines alone, and short suspensions do not reflect the federal penalty.49 CFR §383.51

A CDL holder is convicted a second time of driving a vehicle under the influence. What is the disqualification?

• a.Life, though reinstatement may be possible after 10 years in some cases✓
• b.One year
• c.Three years
• d.Sixty days

A second major offense results in lifetime disqualification, with limited reinstatement possible after 10 years under a state-approved program. One year is the first-offense penalty, three years applies to a first offense while hauling placarded hazmat, and 60 days relates to serious traffic violations.49 CFR §383.51

You are convicted of two serious traffic violations, such as excessive speeding and reckless driving, in separate incidents within a three-year period. What is the result?

• a.Disqualification for one year
• b.Disqualification for 60 days✓
• c.A warning letter only
• d.No effect unless a crash occurred

Two serious traffic violations in three years bring a 60-day disqualification, and a third within the same period brings 120 days. A warning is not the penalty, one year applies to major offenses, and a crash is not required for the disqualification to apply.49 CFR §383.51

You are driving on the interstate and your phone rings. What does federal regulation allow?

• a.Using a hands-free device that requires no more than a single push of a button, with the phone located where you can reach it while belted✓
• b.Holding the phone while using speakerphone
• c.Reading and sending short text messages at a stoplight
• d.Answering by holding the phone to your ear if the call is brief

Federal rules ban holding a mobile phone and ban texting while driving a commercial vehicle, allowing only hands-free operation with a single touch. Brief handheld calls, texting while temporarily stopped in traffic, and holding a phone on speaker all violate the rule.49 CFR §392.82

What is the penalty exposure for a CDL holder convicted of texting while driving a commercial motor vehicle?

• a.Loss of the medical certificate
• b.A verbal warning from the officer
• c.Immediate lifetime disqualification
• d.Substantial civil penalties, and disqualification for 60 days after two convictions in three years or 120 days after three convictions✓

Texting is classified as a serious traffic violation, so repeat convictions bring the 60-day and 120-day disqualifications along with civil penalties for drivers and employers. A warning understates the consequence, medical certification is unrelated, and lifetime disqualification is reserved for major offenses.49 CFR §392.80

How long is a standard medical examiner's certificate valid for an interstate commercial driver with no disqualifying conditions?

• a.Up to 24 months✓
• b.Up to 36 months
• c.Up to 12 months
• d.It never expires once issued

A standard certificate is valid for a maximum of 24 months, and the examiner may issue a shorter certificate when a condition requires monitoring, such as one year for controlled hypertension. Twelve and 36 months are not the standard maximum, and every certificate expires.49 CFR §391.45

You are two hours from your delivery when you realize you are struggling to stay awake and have drifted within your lane. What does the regulation require?

• a.Continue because you still have driving hours available
• b.Stop driving, because a driver whose alertness is impaired by fatigue or illness may not operate a commercial vehicle✓
• c.Continue if you can open a window and drink coffee
• d.Continue but reduce speed by 10 mph

The rule prohibits operating while ability or alertness is impaired by fatigue, illness, or any other cause, regardless of hours remaining. Caffeine, fresh air, and lower speed do not restore alertness, and available hours never authorize driving while impaired.49 CFR §392.3

Which of the following is the most reliable way to prevent driver fatigue?

• a.Turning up the radio and lowering the cab temperature
• b.Drinking energy drinks throughout the run
• c.Taking short naps only after fatigue becomes severe
• d.Getting adequate sleep before the trip and scheduling driving during normal waking hours where possible✓

Only sleep restores alertness, and driving during the body's natural low points such as the early morning hours sharply raises crash risk. Stimulants and sensory tricks mask fatigue temporarily, and waiting until fatigue is severe means you are already impaired.

What does federal regulation require regarding seat belt use in a commercial motor vehicle?

• a.The driver must have the seat belt properly restraining them whenever the vehicle is being operated✓
• b.Seat belts are required only when the vehicle is loaded
• c.Seat belts are required only on interstate highways
• d.Seat belts are optional for drivers with more than five years of experience

A commercial driver must be properly belted any time the vehicle is in operation, with no exception for experience, road type, or load status. Being thrown from the cab is a leading cause of death in truck crashes, which is why the rule has no exceptions.49 CFR §392.16