CDL Basic Vehicle Control

Accelerating, steering, shifting, backing and braking a large vehicle, whose length and weight change every one of those skills.

88 practice questions with answers. These rules are the same in every state.

CDL Basic Vehicle Control quiz

Answer at your own pace. After each question you see the correct answer and why, and at the end a review of what you missed.

Quick quiz: 10 random questions on cdl basic vehicle control; pass with 8 correct.

CDL Basic Vehicle Control questions with answers

Why should a large vehicle be accelerated smoothly and gradually?
1. Rough acceleration can damage the drivetrain and, on a combination, the coupling
2. It reduces wear on the windshield wipers, the mirrors and the cab suspension mounts
3. It keeps the tachometer from reading correctly
4. It shortens the total stopping distance by keeping the linings cooler
Show answer

Answer A: Rough acceleration can damage the drivetrain and, on a combination, the coupling

Jerky throttle inputs put shock loads through the driveline and the coupling, which causes mechanical damage over time.
When traction is poor, such as on packed snow, how should you speed up?
1. As quickly as possible to get through the slippery stretch
2. In the highest gear the transmission allows
3. Very gradually, so the drive wheels do not spin
4. With the retarder switched on for extra grip
Show answer

Answer C: Very gradually, so the drive wheels do not spin

Gentle throttle keeps the drive wheels from breaking traction, because spinning wheels give up both grip and directional control.
How should the steering wheel be held when driving a large vehicle?
1. With one hand resting at the top of the wheel and the other on the gear lever
2. With both hands together at the bottom of the wheel so the arms stay relaxed
3. Loosely, so the wheel can move freely over bumps
4. Firmly with both hands, placed on opposite sides of the wheel
Show answer

Answer D: Firmly with both hands, placed on opposite sides of the wheel

Both hands on opposite sides give the leverage and control needed if a tire drops off the pavement or the wheel is jolted.
What is the correct way to make a normal stop?
1. Push the brake pedal down gradually and bring the vehicle to a smooth stop
2. Press the pedal to the floor and release it repeatedly
3. Shift to neutral and coast until the vehicle stops, then set the parking brake
4. Use the parking brake control instead of the brake pedal so the linings stay cool
Show answer

Answer A: Push the brake pedal down gradually and bring the vehicle to a smooth stop

Steady, progressive pedal pressure keeps the vehicle stable and lets the driver behind you react to a predictable slowdown.
What speed and gear should be used when backing a large vehicle?
1. A steady 10 mph in second reverse
2. As slowly as possible, in the lowest reverse gear
3. As fast as is safe, to shorten the maneuver
4. In neutral, using the parking brake to control speed
Show answer

Answer B: As slowly as possible, in the lowest reverse gear

Backing slowly in the lowest reverse gear keeps the vehicle under precise control and leaves time to correct the path.
Why is backing toward the driver side preferred?
1. The vehicle turns more sharply in that direction
2. It keeps the trailer brakes and the drive tires cooler
3. You can watch the rear of the vehicle directly through the side window
4. It is the only direction the mirrors on a combination vehicle are designed to cover
Show answer

Answer C: You can watch the rear of the vehicle directly through the side window

Backing to the left lets the driver look out the window and see the rear of the vehicle directly instead of relying on a mirror alone.
When a helper guides you while backing, what should be agreed on before you start?
1. How many times to sound the horn each minute
2. Which of the two mirrors the helper will stand in front of while guiding you
3. The gear you will use to pull forward afterward and the route out of the lot
4. A set of hand signals, especially the signal that means stop
Show answer

Answer D: A set of hand signals, especially the signal that means stop

The driver and helper must agree on signals in advance, above all the stop signal, because they usually cannot hear each other.
What should you do before backing into a space you have not used before?
1. Get out and walk around to check the path, the clearance and any obstacles
2. Rely only on the mirrors and the reversing camera so the maneuver takes less time
3. Back at a higher speed to keep momentum through the turn
4. Ask a bystander to hold traffic at both ends of the lot while you reverse
Show answer

Answer A: Get out and walk around to check the path, the clearance and any obstacles

Walking the area first reveals low obstructions, soft ground and objects that never appear in the mirrors.
What is the correct order for a basic double clutch upshift?
1. Push the clutch once and move straight into the higher gear as the engine slows
2. Release the accelerator and push the clutch, shift to neutral, release the clutch, let engine speed drop, push the clutch again and shift to the higher gear
3. Select the higher gear first and then use the clutch
4. Hold the clutch pedal down throughout the whole shift without passing through neutral, so that engine speed never has a chance to fall between the two gear ratios
Show answer

Answer B: Release the accelerator and push the clutch, shift to neutral, release the clutch, let engine speed drop, push the clutch again and shift to the higher gear

Double clutching passes through neutral with the clutch released so engine speed can drop to match the next gear before it is engaged.
What tells a driver when to shift up in a vehicle with a manual transmission?
1. The outside air temperature
2. The air pressure showing in the supply tank and the wet tank
3. Engine speed in rpm together with road speed
4. The position of the trailer hand valve and the clutch pedal
Show answer

Answer C: Engine speed in rpm together with road speed

Shift points are judged from engine rpm and road speed, using the operating range the manufacturer specifies for that engine.
When should a lower gear be selected for a long downgrade?
1. Halfway down, once the speed starts to build
2. Only if the engine stalls on the descent
3. After the brakes begin to fade
4. Before you start down the hill
Show answer

Answer D: Before you start down the hill

The gear is chosen at the top, while speed is still low, because a heavy vehicle already rolling fast may not go into a lower gear at all.
How should speed and gears be handled when approaching a curve?
1. Slow to a safe speed and downshift before entering the curve
2. Brake hard at the sharpest part of the curve, where the vehicle is settled
3. Shift up on entry so the extra torque steadies the vehicle
4. Coast through the curve in neutral
Show answer

Answer A: Slow to a safe speed and downshift before entering the curve

Braking and shifting are completed before the curve so the vehicle is settled and can pull gently through it without upsetting the load.
How do you get more engine braking from an automatic transmission on a downgrade?
1. Move the selector to neutral
2. Select a lower range before starting down
3. Choose the highest available range
4. Hold the accelerator part way down through the descent
Show answer

Answer B: Select a lower range before starting down

Locking the transmission into a lower range keeps engine speed high enough to hold the vehicle back and spares the service brakes.
Why should a retarder be switched off when the road is wet, icy or snowy?
1. It prevents the engine from reaching operating temperature
2. It burns noticeably more fuel in cold weather
3. It can make the drive wheels skid when traction is poor
4. It shuts off the service brakes while it is engaged
Show answer

Answer C: It can make the drive wheels skid when traction is poor

A retarder slows the drive wheels only, and on a slippery surface that braking force can break their traction and start a skid.
What is the correct way to make a right turn in a long vehicle?
1. Swing wide to the left first, then turn right
2. Turn from the left lane whenever the corner is too tight for the trailer
3. Stop in the intersection and back up a few feet if the rear of the trailer will not clear the curb
4. Keep the rear of the vehicle close to the curb and swing wide only as you complete the turn
Show answer

Answer D: Keep the rear of the vehicle close to the curb and swing wide only as you complete the turn

Swinging left before a right turn invites another driver to move into the gap on your right, so any extra width is taken as the turn is finished.
Study tip. Rule out the options you know are wrong first. Two plausible answers are easier to choose between than four.
Why can an empty truck need a longer stopping distance than a loaded one?
1. Empty vehicles are normally driven at higher speeds on the same roads
2. The trailer brakes are automatically disconnected whenever the trailer is empty
3. An empty vehicle has less traction, so its wheels lock up more easily
4. Air pressure falls whenever the trailer is unloaded
Show answer

Answer C: An empty vehicle has less traction, so its wheels lock up more easily

Brakes and tires are designed for a loaded vehicle, and with little weight on the axles the tires grip less and lock sooner.

Source: oregon.gov
When turning left, what should a driver of a long vehicle do before beginning the turn?
1. Move as far right as possible first, then cut across the intersection
2. Reach the center of the intersection so the rear wheels clear the corner
3. Start the turn early so the trailer stays clear of the oncoming traffic lane
4. Stop in the crosswalk and wait for a gap
Show answer

Answer B: Reach the center of the intersection so the rear wheels clear the corner

The rear wheels follow a tighter path than the front, so the vehicle must reach the center of the intersection before the turn begins.
If an intersection has two lanes marked for left turns, which one should a large vehicle use?
1. The left hand of the two turning lanes
2. Either lane, provided the turn is signaled
3. The through lane beside them
4. The right hand of the two turning lanes
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Answer D: The right hand of the two turning lanes

The outside turning lane leaves room for the rear of the vehicle to swing without striking a vehicle in the adjacent lane.
Total stopping distance is made up of which parts?
1. Perception distance, reaction distance and braking distance
2. Following distance, braking distance and the distance covered while shifting
3. Reaction distance plus the coasting distance before the brakes bite
4. Braking distance on its own
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Answer A: Perception distance, reaction distance and braking distance

The vehicle travels while the hazard is recognized, while the driver moves to the pedal, and again while the brakes slow the vehicle.

Source: oregon.gov
What happens to braking distance when speed is doubled?
1. It stays about the same
2. It becomes about twice as long
3. It becomes about four times longer
4. It becomes about eight times longer
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Answer C: It becomes about four times longer

Braking distance grows with the square of speed, so doubling the speed multiplies both the braking distance and the force of an impact by about four.

Source: oregon.gov
How does a driver keep a vehicle with a manual transmission from rolling back when starting on an upgrade?
1. Shift to neutral before releasing the brake
2. Raise the engine to maximum rpm before releasing the clutch
3. Release the clutch fully and then apply the throttle
4. Partly engage the clutch before the right foot leaves the brake, or hold the vehicle with the parking brake until the engine pulls
Show answer

Answer D: Partly engage the clutch before the right foot leaves the brake, or hold the vehicle with the parking brake until the engine pulls

Something has to hold the vehicle during the instant the foot moves from the brake to the accelerator, and that is either the clutch at its engagement point or the parking brake.

Source: dds.georgia.gov
Why does a driver use pull-ups while backing into a tight space?
1. To let the brakes and the clutch cool down between attempts at the loading dock
2. To keep the engine from stalling
3. To pull forward and start the approach again when the angle is going wrong
4. To give the traffic following you a chance to pass the vehicle
Show answer

Answer C: To pull forward and start the approach again when the angle is going wrong

Stopping, pulling ahead and repositioning fixes a bad angle safely, and there is nothing wrong with needing more than one attempt.
Why should both outside mirrors be checked over and over while backing?
1. One mirror alone already shows the whole area behind the vehicle
2. Each mirror covers only part of the path and neither covers the blind spots, so people and objects can appear without warning
3. The mirrors show how high the load is riding
4. Checking them is what releases the parking brake interlock
Show answer

Answer B: Each mirror covers only part of the path and neither covers the blind spots, so people and objects can appear without warning

Working both mirrors in turn is the only way to follow the whole path of a vehicle you cannot see behind.
As a long vehicle goes around a corner, how do the rear wheels travel compared with the front wheels?
1. They follow a tighter path, closer to the inside of the turn
2. They follow exactly the same path as the front wheels do
3. They swing outside the path of the front wheels by a widening margin
4. They lift clear of the pavement
Show answer

Answer A: They follow a tighter path, closer to the inside of the turn

The rear wheels off-track toward the inside of the turn, and the longer the vehicle the bigger the difference, which is why the front must swing wide enough to keep the rear off the curb.
What is the correct order for a double clutch downshift?
1. Brake hard first and let engine speed fall before selecting the gear
2. Push the clutch once and pull straight down into the lower gear
3. Shift to neutral and coast until road speed matches the lower gear
4. Release the accelerator and push the clutch to reach neutral, release the clutch and press the accelerator to raise engine speed, then push the clutch again and select the lower gear
Show answer

Answer D: Release the accelerator and push the clutch to reach neutral, release the clutch and press the accelerator to raise engine speed, then push the clutch again and select the lower gear

A lower gear turns faster than the one being left, so engine speed has to be raised in neutral before that gear will engage cleanly.
How should a driver use brakes fitted with an antilock system during an emergency stop?
1. Pump the pedal rapidly
2. Use the parking brake control instead of the pedal so the system can act
3. Brake as usual and keep enough pressure to stay in control while steering around the hazard
4. Release the pedal each time the wheels begin to slow, and then press it down hard again straight away
Show answer

Answer C: Brake as usual and keep enough pressure to stay in control while steering around the hazard

The system only works when the brakes are applied hard enough for it to act, so the driver keeps pressure on and steers while the system prevents lockup.

Source: dds.georgia.gov
You must steer hard around an obstacle at highway speed. What is the correct technique?
1. Brake firmly all the way through the steering movement so the vehicle sheds as much speed as possible while it turns
2. Avoid braking while turning, turn only as far as needed, and countersteer as soon as the obstacle is passed
3. Hold the wheel with one hand at the top so it can be turned faster
4. Shift into neutral before turning
Show answer

Answer B: Avoid braking while turning, turn only as far as needed, and countersteer as soon as the obstacle is passed

Braking during a hard steering input can lock the wheels and start a skid, and turning back at once keeps the vehicle from running off the far side of the road.

Source: dds.georgia.gov
Your right wheels drop off the pavement onto a soft shoulder. What is the correct recovery?
1. Stay on the shoulder, ease off the accelerator, brake gently only once speed is down to about 20 mph, then steer back sharply and countersteer at once
2. Steer back onto the pavement immediately, before speed drops
3. Brake hard right away to stop on the shoulder
4. Turn the wheel hard to the left and accelerate
Show answer

Answer A: Stay on the shoulder, ease off the accelerator, brake gently only once speed is down to about 20 mph, then steer back sharply and countersteer at once

Bringing speed down on the shoulder first avoids a violent sideways jolt, and countersteering the instant the tires are back on the pavement keeps the vehicle out of the next lane.

Source: dds.georgia.gov
How does a front tire failure usually feel to the driver?
1. The engine loses power
2. The back of the vehicle sways from side to side over the whole lane
3. The air pressure gauge climbs quickly and the buzzer sounds
4. The steering suddenly becomes heavy and pulls to one side
Show answer

Answer D: The steering suddenly becomes heavy and pulls to one side

A failed front tire loads the steering and makes the wheel feel heavy, while a rear tire failure shows up as the back end swaying.

Source: dds.georgia.gov
A tire blows out at highway speed. What should the driver do first?
1. Brake hard to stop as quickly as possible before the rim reaches the bare pavement
2. Steer sharply onto the shoulder
3. Hold the steering wheel firmly, stay off the brake and let the vehicle slow down
4. Shift immediately into the lowest gear the transmission will take
Show answer

Answer C: Hold the steering wheel firmly, stay off the brake and let the vehicle slow down

Braking while a tire is gone can pull the vehicle out of line, so the driver keeps it straight and lets speed fall before easing off the road.
What does the commercial driver manual tell you to do with the parking brake when you leave your vehicle?
1. Leave it released so the air system can build pressure faster
2. Apply the parking brake every time you leave the vehicle
3. Apply the parking brake only when the vehicle is loaded
4. Apply the parking brake only when the vehicle is parked on a grade
Show answer

Answer B: Apply the parking brake every time you leave the vehicle

The manual is explicit that the parking brake goes on whenever the driver leaves the vehicle, because once nobody is at the controls it is the only thing holding it.

Source: oregon.gov
In a vehicle with a manual transmission, when should the clutch be pushed in during a normal stop?
1. Just before the engine would stall, when the vehicle is nearly stopped
2. As soon as the brake pedal is touched, so the engine is never dragged down
3. Repeatedly, pumping it in time with the brake pedal
4. Never, because the engine is meant to stall
Show answer

Answer A: Just before the engine would stall, when the vehicle is nearly stopped

Staying in gear until the last moment keeps engine braking and steady control, so the clutch goes down only when the engine is about to drop below idle.
Why must you never coast down a hill in neutral or with the clutch pushed in?
1. The transmission oil pump stops working and the gears seize within a few seconds
2. The retarder switches itself on and can lock the drive wheels without any warning
3. You lose the braking effect of the engine and your brakes may overheat and fail
4. The speedometer stops reading, so you cannot judge the speed of the vehicle
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Answer C: You lose the braking effect of the engine and your brakes may overheat and fail

Engine braking is what keeps a heavy vehicle in check on a grade; coasting throws it away and leaves the service brakes to do all the work until they overheat.

Source: oregon.gov
You miss a gear while double clutching and the transmission is stuck in neutral. What should you do?
1. Force the shift lever into the gear while pressing the brake pedal to slow the vehicle down
2. Return to neutral, release the clutch, bring engine speed to match road speed and try again
3. Shut the engine off and restart it, which will let the gears line up again on their own
4. Pull out the parking brake knob until the vehicle stops, then select the gear from a standstill
Show answer

Answer B: Return to neutral, release the clutch, bring engine speed to match road speed and try again

Forcing the lever damages the gears; matching the engine speed to the road speed lets the gear engage cleanly on the next try.

Source: oregon.gov
For a modern truck with low-friction parts and a streamlined shape, which gear should be used going down a grade?
1. The same gear that was needed to climb the same grade
2. One gear higher than the one used to climb the same grade
3. The highest gear available, so the engine can turn slowly and stay cool
4. A gear lower than the one needed to climb the same grade
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Answer D: A gear lower than the one needed to climb the same grade

Newer trucks roll more freely than older ones, so the old rule of using the climbing gear no longer holds; a lower gear is needed for enough engine braking.

Source: oregon.gov
What is the main purpose of a retarder fitted to a heavy vehicle?
1. To hold the vehicle in place on a grade when it is parked with the engine off
2. To help slow the vehicle and reduce the need to use the service brakes
3. To keep the drive wheels from spinning when starting on wet pavement
4. To limit the top speed of the vehicle on level highway to the legal limit
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Answer B: To help slow the vehicle and reduce the need to use the service brakes

Exhaust, engine, hydraulic and electric retarders all slow the vehicle so the brakes stay cool and wear less, especially on grades.

Source: oregon.gov
Why is braking while in a curve dangerous in a heavy vehicle?
1. The wheels lock more easily and the vehicle can skid
2. The brake lights blind drivers behind you on the inside of the curve
3. The retarder is disabled automatically whenever the steering wheel is turned
4. The engine stalls because fuel flows away from the pickup in the tank
Show answer

Answer A: The wheels lock more easily and the vehicle can skid

Tires already using their grip to turn have little left for braking, so hard braking in a curve locks the wheels; slow down before the curve instead.

Source: oregon.gov
Which description matches controlled braking during an emergency stop?
1. Apply the brakes fully, release them when the wheels lock, and then apply them fully again
2. Pump the pedal rapidly several times a second so the wheels never have time to lock up
3. Apply the parking brake and the service brake together while turning sharply toward the shoulder
4. Apply the brakes as hard as you can without locking the wheels and keep steering movements small
Show answer

Answer D: Apply the brakes as hard as you can without locking the wheels and keep steering movements small

Controlled braking keeps the wheels rolling just short of lockup, which gives the shortest stop while you keep the ability to steer.

Source: oregon.gov
A hazard suddenly appears ahead and you must act. Which is usually the faster way to avoid it in a heavy vehicle?
1. Braking to a full stop, because a heavy vehicle stops faster than it turns
2. Steering around it, because you can usually turn faster than you can stop
3. Sounding the horn, because the hazard will usually clear before you reach it
4. Downshifting two gears, because engine braking stops the vehicle quicker than the brakes
Show answer

Answer B: Steering around it, because you can usually turn faster than you can stop

Stopping distance at speed is very long, so a quick turn out of the way, when there is room, avoids the crash sooner than braking.

Source: oregon.gov
The brake pedal goes to the floor in a vehicle with hydraulic brakes. What can you do to build some braking pressure?
1. Hold the pedal on the floor and turn the engine off to stop the power assist from working
2. Pump the brake pedal rapidly, which may bring back enough pressure to slow the vehicle
3. Shift into a higher gear so the vehicle can roll to a smooth stop on its own momentum
4. Turn the steering wheel back and forth quickly to scrub off speed with the front tires
Show answer

Answer B: Pump the brake pedal rapidly, which may bring back enough pressure to slow the vehicle

Pumping can restore some hydraulic pressure; along with downshifting and the parking brake it is one of the ways to stop when the pedal fails.

Source: oregon.gov
Your brakes have failed and you decide to use the parking brake to slow down. Why should you hold the release button or lever while doing so?
1. So the brake applies more slowly and the drums do not heat up as quickly during the stop
2. So the warning buzzer stays off and does not distract you while you bring the vehicle down
3. So the spring pressure is doubled and the vehicle stops in a much shorter distance
4. So you can release the brake at once if the wheels lock and the vehicle starts to skid
Show answer

Answer D: So you can release the brake at once if the wheels lock and the vehicle starts to skid

The parking brake can lock the wheels; keeping your hand on the release lets you let go the moment a skid starts and regain control.

Source: oregon.gov
Your brakes have failed on a downgrade and there is no escape ramp in sight. What is the best choice?
1. Steer into an open field or onto a side road that flattens out or climbs uphill
2. Steer toward the nearest guardrail and scrape along it to slow the vehicle down
3. Pull into the oncoming lane, where the drivers can see you and move out of your way
4. Stay in the lane and keep sounding the horn until the road levels off on its own
Show answer

Answer A: Steer into an open field or onto a side road that flattens out or climbs uphill

A flat or uphill escape route uses gravity and rolling resistance to stop the vehicle; take it as soon as you see it, because the longer you wait the faster you go.

Source: oregon.gov
You are making a right turn and cannot complete it without swinging into the oncoming lane. An oncoming car is approaching. What should you do?
1. Wait and let the oncoming vehicle pass before completing the turn, and do not back up
2. Back up a few feet to open the angle and then complete the turn ahead of the car
3. Flash your headlights so the oncoming driver stops and lets you finish the turn first
4. Complete the turn quickly, because the oncoming vehicle must yield to a larger vehicle
Show answer

Answer A: Wait and let the oncoming vehicle pass before completing the turn, and do not back up

The oncoming vehicle has the lane; backing up in traffic is dangerous, so hold your position and finish the turn once the way is clear.

Source: oregon.gov
The rear wheels of your vehicle lock during braking and the rear starts to slide sideways. What should you do first?
1. Stop braking so the rear wheels can roll again, then steer quickly in the direction you want to go
2. Brake harder so the front wheels lock as well and the vehicle slides in a straight line
3. Push in the clutch and press the accelerator to pull the rear of the vehicle back in line
4. Turn the steering wheel opposite to the slide and hold it there until the vehicle is fully stopped
Show answer

Answer A: Stop braking so the rear wheels can roll again, then steer quickly in the direction you want to go

Locked wheels have no side grip; releasing the brakes restores traction and then countersteering brings the vehicle back into line.

Source: oregon.gov
Your drive wheels start to spin and the rear begins to slide while you accelerate on a slick surface. What should you do?
1. Press the accelerator harder to power the drive wheels through the slippery patch
2. Stop accelerating and, if the vehicle has a manual transmission, push in the clutch
3. Apply the brakes firmly so the drive wheels stop spinning immediately and grip again
4. Turn the steering wheel sharply in the direction the rear is sliding and hold it there
Show answer

Answer B: Stop accelerating and, if the vehicle has a manual transmission, push in the clutch

An acceleration skid ends when the drive wheels stop pushing, so easing off the throttle and disengaging the clutch lets them regain grip.

Source: oregon.gov
Study tip. When two answers both seem legal, pick the one that is safer for everyone on the road. That is how most tests are written.
What is the most common cause of a front-wheel skid, where the vehicle keeps going straight even though you turn the wheel?
1. Carrying too much weight on the drive axles instead of the steering axle
2. Driving too fast for the conditions
3. Using new tires on the steering axle while the rear tires are worn
4. Leaving the parking brake partly applied while driving on a dry road
Show answer

Answer B: Driving too fast for the conditions

A front-wheel skid usually comes from too much speed for the traction available; the only cure is to let the vehicle slow down and stop turning or braking so hard.

Source: oregon.gov
Which of these is a major cause of skids in heavy vehicles?
1. Using low beams during the day and driving in the center lane of a wide freeway
2. Keeping a following distance of more than seven seconds at highway speed on dry roads
3. Over-braking, over-steering, over-acceleration or driving too fast for conditions
4. Running the engine at the lower end of its normal rpm range on level ground
Show answer

Answer C: Over-braking, over-steering, over-acceleration or driving too fast for conditions

Skids happen when the tires are asked for more grip than the road can give, which happens through braking, steering or accelerating too hard or simply too much speed.

Source: oregon.gov
You have countersteered to correct a rear-wheel skid and the vehicle straightens out. What must you be ready for next?
1. The engine will stall, so you must restart it before the vehicle stops rolling
2. The brakes will lock automatically, so you must release the parking brake at once
3. The tires will lose all their pressure, so you must pull over and inspect them
4. The vehicle may swing back the other way, so you must steer again to correct it
Show answer

Answer D: The vehicle may swing back the other way, so you must steer again to correct it

A vehicle coming out of a skid tends to overshoot and swing in the opposite direction, and the driver must be ready to countersteer a second time.

Source: oregon.gov
Which factors determine a safe speed for a long, steep downgrade?
1. Only the posted speed limit for the road, since it is always set with the heaviest trucks in mind
2. The number of trailers being pulled behind you and the color of the escape ramp signs posted along the route ahead
3. The steepness and length of the grade, the weight of the vehicle and cargo, and the road and weather conditions
4. The engine size alone, because a larger engine always gives more engine braking on a grade
Show answer

Answer C: The steepness and length of the grade, the weight of the vehicle and cargo, and the road and weather conditions

Gravity, weight and traction all decide how fast a heavy vehicle can safely descend, which is why signs often post lower speeds for trucks on grades.

Source: oregon.gov
How are the extra gears of a multi-speed rear axle or auxiliary transmission usually controlled?
1. With a separate floor pedal located to the left of the clutch pedal
2. Automatically by the engine computer, without any input from the driver
3. With a lever on the dashboard that must only be moved while the vehicle is stopped
4. With a selector knob or switch on the gearshift lever of the main transmission
Show answer

Answer D: With a selector knob or switch on the gearshift lever of the main transmission

A range selector on the shift lever lets the driver choose the extra gear range while shifting the main transmission.

Source: oregon.gov
A 40 foot straight truck and a 70 foot tractor-trailer make the same right turn. Which needs more room and why?
1. The straight truck, because a shorter wheelbase makes the rear wheels swing wider
2. The tractor-trailer, because the longer the vehicle the farther inside the rear wheels track
3. Both need the same room, because off-tracking depends only on the speed of the turn
4. The straight truck, because its rear wheels follow outside the path of the front wheels
Show answer

Answer B: The tractor-trailer, because the longer the vehicle the farther inside the rear wheels track

Off-tracking grows with the distance between the front and rear axles, so the longer combination cuts the corner much more sharply and needs extra room.

Source: oregon.gov
Why is a sudden, sharp lane change dangerous in a loaded heavy vehicle?
1. The drive wheels lose all power because the engine cuts fuel during any quick steering movement
2. The exhaust brake engages by itself and locks the drive axle for as long as the wheel is turned
3. The service brakes apply on their own and pull the rear of the vehicle toward the outside of the move
4. The vehicle can lean far enough to roll over, especially when the load sits high
Show answer

Answer D: The vehicle can lean far enough to roll over, especially when the load sits high

A quick swerve throws the weight of a tall, heavy load sideways, and a rollover can begin before the tires ever slide.

Source: oregon.gov
Within total stopping distance, what exactly is perception distance?
1. The distance the vehicle keeps traveling while the brakes are slowing it to a full stop
2. The distance the vehicle travels once your foot has begun moving toward the brake pedal
3. The distance you are told to keep between your vehicle and the one ahead of you in traffic
4. The distance traveled from the moment your eyes see a hazard until your brain identifies it
Show answer

Answer D: The distance traveled from the moment your eyes see a hazard until your brain identifies it

Perception distance covers only the time between seeing a hazard and recognizing it as a hazard, before any physical reaction begins.

Source: fmcsa.dot.gov
Which parts of total stopping distance can a driver shorten simply by staying alert and looking far ahead?
1. Braking distance alone, since an alert driver applies the brakes much harder than usual
2. Perception distance and reaction distance
3. None of them, because every part is fixed by the weight and the brakes of the vehicle
4. Reaction distance and braking distance, because both depend on how quickly you respond
Show answer

Answer B: Perception distance and reaction distance

Alertness shortens the time spent recognizing a hazard and moving your foot to the pedal; braking distance depends on speed, weight, brakes and the road surface.

Source: fmcsa.dot.gov
What does the tachometer on the dashboard of a heavy truck show?
1. The road speed of the vehicle, measured at the drive axle rather than at the wheels
2. The distance the vehicle has covered since the last scheduled service was carried out
3. The pressure of the oil being delivered to the engine bearings while it runs
4. How fast the engine is turning, in revolutions per minute
Show answer

Answer D: How fast the engine is turning, in revolutions per minute

The tachometer reads engine speed in rpm, which is what a driver uses to judge shift points in a vehicle with a manual transmission.

Source: oregon.gov
What is the danger of letting engine speed climb past the top of the rated rpm range before you shift?
1. The transmission selects the next gear by itself and you lose control of the shift
2. You can damage the engine, so the shift should be made before that point
3. Fuel consumption falls away sharply because the engine is at its most efficient there
4. The engine brake or retarder switches itself on to protect the rest of the drivetrain
Show answer

Answer B: You can damage the engine, so the shift should be made before that point

Every engine has a rated operating range; running above it can cause serious engine damage, so the upshift belongs at the top of that range, not beyond it.

Source: oregon.gov
You normally pull an empty trailer, but today the same tractor is loaded to its legal maximum. What changes about getting under way?
1. You may need to start in a lower gear, since the load takes more pulling power
2. You should start in the same gear but release the clutch far more quickly
3. You should start in a higher gear so the engine is not working near its limit
4. You should hold the clutch at the friction point until the vehicle reaches walking pace
Show answer

Answer A: You may need to start in a lower gear, since the load takes more pulling power

The heavier the load, the lower the gear needed to get the vehicle rolling without lugging or stalling the engine.

Source: oregon.gov
While double clutching, what goes wrong if you take too long between the two clutch movements?
1. Engine speed falls too far and the gear becomes hard or impossible to engage
2. The clutch brake engages and stops the input shaft while the vehicle is still rolling fast
3. The transmission will lock itself in neutral until the vehicle has come to a complete stop
4. The engine will race up to its governed speed and stay there until you shift again
Show answer

Answer A: Engine speed falls too far and the gear becomes hard or impossible to engage

Double clutching only works while engine speed and road speed still match; a slow shift lets rpm drop away and the gear will not go in.

Source: oregon.gov
Why must the downshift be finished before you reach a steep downgrade or a sharp curve rather than during it?
1. Because the transmission is mechanically locked out of the lower gears on any grade
2. Because a shift on a grade will burn the clutch out within a few hundred yards
3. Because engine braking only works if the gear was selected while on level ground
4. Because once your speed is too high you may not get into any gear at all
Show answer

Answer D: Because once your speed is too high you may not get into any gear at all

If you wait until speed has built up, the lower gear may refuse to engage and you can be left in neutral with no engine braking at all.

Source: oregon.gov
Why should a driver avoid shifting gears in the middle of a turn at an intersection?
1. The gearbox can be damaged whenever the front wheels are turned away from straight
2. The rear wheels will off-track much further than they would in the same gear
3. Turn signals cancel themselves as soon as the gear lever is moved out of position
4. Shifting during the turn takes a hand off the wheel and can cost you control
Show answer

Answer D: Shifting during the turn takes a hand off the wheel and can cost you control

Pick the gear before you begin turning; shifting in the turn removes a hand from the wheel and can interrupt power just when you need steady control.

Source: oregon.gov
An automatic transmission is left in its normal drive position as the vehicle rolls down a long grade. What does it tend to do?
1. Shift up as road speed rises, so engine braking falls away
2. Hold the gear it was in at the top of the grade for the whole descent
3. Shift down automatically as soon as it senses the grade, giving extra braking
4. Slip into neutral to protect the torque converter from the increasing road speed
Show answer

Answer A: Shift up as road speed rises, so engine braking falls away

An automatic left in drive keeps upshifting as speed builds, which is the opposite of what you want on a grade; that is why the driver must select a low range.

Source: oregon.gov
Apart from the risk of stalling, why is rolling backwards when starting on an upgrade so serious in a heavy vehicle?
1. The engine can flood and stall, leaving you blocking the whole of the intersection
2. Rolling back drains the air system and drags the trailer brakes for several miles
3. The transmission can jump into a higher gear the moment you press the accelerator
4. You can strike the vehicle behind you, which is often much closer than you think
Show answer

Answer D: You can strike the vehicle behind you, which is often much closer than you think

You cannot see how close the vehicle behind has stopped, and even a short roll back is enough to hit it.

Source: oregon.gov
Besides being uncomfortable, what can a series of hard, jerky brake applications do to a loaded combination?
1. Shift the load and push the trailer out of line behind the tractor
2. Shut the antilock system down until the engine has been stopped and restarted
3. Use noticeably more fuel than one long steady application of the same brakes
4. Set the parking brake by itself before the vehicle has actually come to rest
Show answer

Answer A: Shift the load and push the trailer out of line behind the tractor

Sudden, uneven braking can move cargo forward and upset the alignment of a trailer, which is why stops should be made smoothly.

Source: oregon.gov
How do you avoid the sharp lurch that comes at the very end of a stop in a heavy vehicle?
1. Ease off the brake pressure just before the vehicle actually comes to rest
2. Increase brake pressure steadily right through until the vehicle has fully stopped
3. Release the brake completely about one vehicle length before the stopping point
4. Pull the parking brake on for the last few feet so the service brakes can release
Show answer

Answer A: Ease off the brake pressure just before the vehicle actually comes to rest

A smooth stop is finished by reducing pedal pressure as the vehicle settles, so the suspension does not rock the cab and the load forward.

Source: oregon.gov
You are pulling away from a curb in a 65 foot combination. Besides traffic, what must you watch?
1. The tachometer, which must stay below half of its range until you are clear
2. The trailer wheels, which stay close to the curb and can strike it or an object on it
3. The steer tires, which will scrub badly unless the wheel is held perfectly straight
4. The mirrors on the passenger side only, since the driver side is already in view
Show answer

Answer B: The trailer wheels, which stay close to the curb and can strike it or an object on it

Because of off-tracking, the rear wheels follow a tighter path than the front, so they stay near the curb while the cab is already out in the lane.

Source: oregon.gov
You are backing a tractor-trailer in a straight line and the trailer starts to drift to the left. What is the standard correction?
1. Turn the top of the steering wheel hard to the right until the rig lines up again
2. Stop, set the brakes and wait for the trailer to settle before you carry on back
3. Hold the wheel still and add throttle so that the trailer straightens itself out
4. Turn the top of the steering wheel a little to the left, toward the drift
Show answer

Answer D: Turn the top of the steering wheel a little to the left, toward the drift

Small corrections made in the direction the trailer is drifting bring it back into line; large or opposite movements make the drift worse.

Source: oregon.gov
You have backed into the same loading bay every week for a year. How often should you still get out and walk to the rear before backing?
1. Only when the yard is busy enough that people may be moving around behind you
2. Only when a helper is not available to stand at the rear and guide you in
3. Only on the first visit of the day, since nothing changes during a single shift
4. Every time, since the area can change while you are away from it
Show answer

Answer D: Every time, since the area can change while you are away from it

A familiar space is no guarantee; vehicles, pallets, people and overhead obstructions appear between one visit and the next, so you check on every occasion.

Source: oregon.gov
The only way into a customer yard forces you to back toward the right, or blind, side of the vehicle. What should you do?
1. Refuse the delivery, since backing to the blind side breaks a federal safety rule
2. Back at a steady speed so that the maneuver is over as quickly as possible
3. Open the passenger door and lean across the cab so that you can watch that side
4. Use a helper and get out to check the path more often than you normally would
Show answer

Answer D: Use a helper and get out to check the path more often than you normally would

Blind side backing is allowed but far riskier, so it calls for a spotter you can see and for repeated checks of the path on foot.

Source: oregon.gov
Why must the steering wheel be moved only a small amount at a time while backing?
1. Because the power steering pump cannot keep up with large movements in reverse
2. Because a small turn of the wheel produces a large change at the rear of the vehicle
3. Because the steering box can be damaged if it is turned quickly while in reverse
4. Because the mirrors take several seconds to show any movement of the trailer at all
Show answer

Answer B: Because a small turn of the wheel produces a large change at the rear of the vehicle

In reverse, the effect of the steering is greatly magnified at the back of the vehicle, so a small correction is usually all that is needed.

Source: oregon.gov
Your truck has a backup alarm that sounds whenever reverse is selected. What may a driver rely on it for?
1. Proof that the area behind the vehicle has been cleared of people before you move
2. Confirmation that the reverse lamps and the rear reflectors are working correctly
3. A legal substitute for getting out and looking whenever the yard is a private one
4. Very little; it warns some people but cannot show you what is behind the vehicle
Show answer

Answer D: Very little; it warns some people but cannot show you what is behind the vehicle

An alarm may not be heard over yard noise or by someone wearing hearing protection, so it never replaces looking at the path yourself.

Source: oregon.gov
You are about to back across a quiet street into a driveway. Which of these is good practice before you start to move?
1. Switch the headlights to high beam so that traffic behind you can see the truck
2. Turn on the four-way flashers and sound the horn to alert anyone nearby
3. Set the trailer brakes with the hand valve so the trailer cannot swing to either side
4. Release the parking brake early so the vehicle can roll back under its own weight
Show answer

Answer B: Turn on the four-way flashers and sound the horn to alert anyone nearby

Warning other road users and pedestrians before a reverse maneuver gives them the chance to stop or move clear before the vehicle starts back.

Source: oregon.gov
Why should a long vehicle never swing out to the left before starting a right turn?
1. It places the drive wheels on the part of the road with the least available traction
2. It makes the whole turn take longer and blocks the intersection for other traffic
3. It makes the trailer wheels ride up over the curb on the far side of the street
4. Another driver may read it as a left turn or pass on your right
Show answer

Answer D: Another driver may read it as a left turn or pass on your right

Swinging left opens a gap on your right that a car will move into, and it also sends a false message about which way you are going.

Source: oregon.gov
During a right turn in a tractor-trailer, what are you looking for in the right hand mirror?
1. The load, to confirm that none of the tiedowns have come loose during the turn
2. Whether the trailer will clear the curb and whether anything has moved alongside you
3. The angle of the fifth wheel, which shows how far the tractor has turned so far
4. The reflection of the traffic signal, so you can see it once the cab has passed it
Show answer

Answer B: Whether the trailer will clear the curb and whether anything has moved alongside you

The right mirror is what tells you how close the trailer wheels are running to the curb and whether a vehicle or a cyclist has slipped into the space on your right.

Source: oregon.gov
Two vehicles of exactly the same length make a right turn, one gently and one very tightly. What is the effect on off-tracking?
1. Turning more sharply increases off-tracking, so the tight turn needs more room
2. The gentler turn off-tracks more, because the rear wheels are following for longer
3. Off-tracking is fixed by the wheelbase alone and is not affected by the turn at all
4. Off-tracking disappears entirely once the turn is made below about five miles an hour
Show answer

Answer A: Turning more sharply increases off-tracking, so the tight turn needs more room

Off-tracking depends on both the length of the vehicle and the sharpness of the turn; a tighter corner brings the rear wheels further inside the path of the front wheels.

Source: oregon.gov
You are taking a tightly curved highway exit ramp in a long combination. Where should the tractor be placed within the lane?
1. Toward the inside of the curve, so the trailer has the whole ramp to itself
2. Exactly in the center of the ramp, so the load stays balanced through the bend
3. Hard against the outer guardrail, so the mirrors clear the inside of the curve
4. Toward the outside of the curve, leaving room for the trailer to track inside
Show answer

Answer D: Toward the outside of the curve, leaving room for the trailer to track inside

Because the trailer wheels cut to the inside of the curve, the tractor has to be kept out toward the outer edge so the trailer does not drop a wheel off the inside edge.

Source: oregon.gov
Study tip. One test a day for a week beats seven tests in one evening: spaced practice is what makes rules stick.
A straight truck has a long body behind the rear axle. What happens to that overhang in a sharp left turn?
1. It stays within the path of the rear wheels for the whole of the turn
2. It swings out only when the truck is empty and the rear springs are unloaded
3. It drops noticeably lower, so the rear of the body can scrape the road surface
4. It swings out to the right and can strike a vehicle or an object on that side
Show answer

Answer D: It swings out to the right and can strike a vehicle or an object on that side

Body that hangs behind the rear axle swings the opposite way to the turn, so the tail of the truck sweeps out into the next lane or over the curb.

Source: oregon.gov
You need fuel and the canopy over the pumps is low. What is the safe way to handle the clearance?
1. Drive under slowly at an angle, since that reduces the height needed by the trailer
2. Stop and check the height at the entrance and at the way out before committing
3. Follow another tractor-trailer through, since it proves the clearance is adequate
4. Let air out of the suspension bags at the pumps to lower the vehicle for the exit
Show answer

Answer B: Stop and check the height at the entrance and at the way out before committing

Clearance can differ at the entry, under the canopy and at the exit, and a sloping approach changes the effective height, so both ends have to be checked.

Source: oregon.gov
You are unsure whether your vehicle will fit through a narrow gate. What should you do?
1. Stop, get out and look, and take another route if the space is not clearly enough
2. Fold both mirrors in, since they are the widest point of any commercial vehicle
3. Take it slowly at a shallow angle and watch the mirrors as you pass through
4. Ask the customer to confirm the width, since the yard owner is responsible for it
Show answer

Answer A: Stop, get out and look, and take another route if the space is not clearly enough

Clearance is never guessed at from the seat; you look at it on foot and go round rather than trying a gap that may be too tight.

Source: oregon.gov
You must leave the vehicle parked on a slight grade. What adds security beyond setting the parking brake?
1. Leaving the transmission in the highest gear so that it cannot possibly roll away
2. Leaving the engine running so that the compressor keeps the brake system charged
3. Turning the steering wheel away from the curb so that the front tires stay straight
4. Chocking the wheels so the vehicle cannot roll if the brake bleeds off
Show answer

Answer D: Chocking the wheels so the vehicle cannot roll if the brake bleeds off

Chocks hold the vehicle mechanically and are the standard backup whenever a parked vehicle could roll.

Source: oregon.gov
Why does the manual insist on a firm grip with both hands on opposite sides of the steering wheel?
1. A hard bump can pull the wheel out of a loose grip
2. A firm grip stops the power steering pump from cutting out at low engine speed
3. It keeps the front tires from wearing unevenly across the tread over time
4. It prevents the steering column lock from setting while the vehicle is moving
Show answer

Answer A: A hard bump can pull the wheel out of a loose grip

Hitting a curb or a deep pothole can jerk the wheel violently, and only a firm two-handed grip keeps the vehicle under control when that happens.

Source: oregon.gov
What is wrong with resting your foot on the clutch pedal between shifts?
1. It keeps the clutch brake applied and will overheat the transmission input shaft
2. It slowly wears the clutch out, because the pressure plate is never fully engaged
3. It stops the engine from reaching the top of its rated operating range in any gear
4. It causes the transmission to select neutral automatically at low road speeds
Show answer

Answer B: It slowly wears the clutch out, because the pressure plate is never fully engaged

Any weight on the pedal partly disengages the clutch, so it slips and wears; the foot belongs off the pedal once the shift is finished.

Source: oregon.gov
You are stopped in traffic on a steep upgrade behind another truck. How much space should you leave in front?
1. Enough that you can pull away without rolling back into the vehicle behind you
2. About half a vehicle length, which is enough for any heavy vehicle on a grade
3. As little as possible, so nobody can move into the gap ahead of your vehicle
4. Exactly one vehicle length, measured from your bumper to the trailer in front
Show answer

Answer A: Enough that you can pull away without rolling back into the vehicle behind you

Room ahead lets you get moving smoothly on a grade instead of having to hold the vehicle perfectly still or roll back toward the traffic behind.

Source: oregon.gov
Which set of maneuvers makes up the basic control skills part of the commercial driving test?
1. Emergency braking, skid recovery, hill starts and a timed lane change on the road
2. Coupling, uncoupling, air brake tests and a full walkaround of the tractor unit
3. Highway merging, downgrade descent, railroad crossings and an intersection sequence
4. Straight line backing, offset backing, parallel parking and alley docking
Show answer

Answer D: Straight line backing, offset backing, parallel parking and alley docking

The basic control skills test is carried out off the road and consists of low speed exercises such as straight line backing, offset backing, parallel parking and the alley dock.

Source: ecfr.gov
What condition should the fifth wheel be in before you back under a trailer?
1. Locked closed and greased, so the kingpin slides across the plate without catching
2. Tilted down at the front, with the release handle pulled out to the locked position
3. Jaws open, plate greased, and the fifth wheel tilted down toward the rear
4. Slid fully forward on its rails and locked there, whatever the weight of the load
Show answer

Answer C: Jaws open, plate greased, and the fifth wheel tilted down toward the rear

The jaws have to be open to take the kingpin, the plate must be lubricated to prevent hard steering, and the fifth wheel is tilted down at the rear so the trailer apron can ride up onto it.

Source: oregon.gov
Why should you never back under a trailer whose landing gear is resting on soft or muddy ground?
1. The tires of the tractor will lose traction and spin before the kingpin is engaged
2. The trailer brakes cannot hold on a soft surface, so the trailer will roll backwards
3. The landing gear can sink or collapse and the trailer can drop or tip over
4. Mud on the fifth wheel plate makes the locking jaws close on the head of the kingpin
Show answer

Answer C: The landing gear can sink or collapse and the trailer can drop or tip over

Soft ground lets the landing gear sink under the load being transferred to it, and a trailer that drops or topples during coupling is extremely dangerous.

Source: oregon.gov
During uncoupling, when may the fifth wheel locking lever be released?
1. As soon as the tractor parking brake is applied and the air lines are disconnected
2. At any point, provided the trailer wheels have been chocked on both sides first
3. Only after the tractor has been eased forward far enough to unload the kingpin fully
4. Only after the landing gear is down and taking the weight of the trailer
Show answer

Answer D: Only after the landing gear is down and taking the weight of the trailer

The landing gear has to be supporting the trailer before the lock is released; otherwise the trailer nose can drop as soon as the tractor pulls out.

Source: oregon.gov
You are dropping a loaded trailer in a yard. How far should the landing gear be lowered?
1. Until the pads make firm contact and the trailer weight is just off the fifth wheel
2. Until the pads are about an inch clear of the surface, ready to take the weight
3. Until the trailer nose is lifted clear of the fifth wheel by several inches
4. Until the crank turns freely again, which shows the trailer is properly supported
Show answer

Answer A: Until the pads make firm contact and the trailer weight is just off the fifth wheel

Cranking down until the gear is firmly on the ground and just lifting the load off the fifth wheel makes the trailer stable and lets the tractor pull out cleanly.

Source: oregon.gov
Where should a trailer be dropped, and what else does the driver do before pulling out from under it?
1. On any paved surface, leaving the air lines connected so the trailer brakes stay set
2. On a slight downgrade, so the tractor can be driven out without using engine power
3. On solid level ground, with the trailer wheels chocked if it may roll
4. On the softest ground available, so that the landing gear pads settle in and grip
Show answer

Answer C: On solid level ground, with the trailer wheels chocked if it may roll

A dropped trailer must sit on ground that will carry the landing gear without sinking, and chocks stop it rolling once the tractor and its air supply are gone.

Source: oregon.gov