Arizona MVD CDL General Knowledge Practice Test 6
- Questions50
- Correct to pass40
- Passing score80%
- Minimum age18 years
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1. Which set of maneuvers makes up the basic control skills part of the commercial driving test?
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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.
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2. How much free play in the steering wheel is enough to make a vehicle hard to steer and should be reported?
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Answer B: More than 10 degrees, roughly 2 inches of movement at the rim of a 20 inch wheel
Excess play means steering input is lost before the wheels respond, and more than about 10 degrees is treated as a defect.
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3. How should the steering wheel be held when driving a large vehicle?
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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.
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4. What is the purpose of the torque rods or radius rods you check on the suspension?
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Answer A: They hold the axle in alignment with the frame under braking and acceleration
Torque rods resist the twisting and fore and aft forces on the axle, so a cracked or missing rod lets the axle move out of alignment.
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5. Apart from the risk of stalling, why is rolling backwards when starting on an upgrade so serious in a heavy vehicle?
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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.
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6. A company mechanic serviced your truck this morning and signed the work order. Do you still have to inspect the vehicle?
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Answer B: Yes, the driver is still responsible for being satisfied the vehicle is safe
Shop work does not transfer the duty; the driver who takes the vehicle out remains responsible for being satisfied it is in safe operating condition.
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7. Which of these is a major cause of skids in heavy vehicles?
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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.
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8. You are backing into a yard where electrical wires cross overhead. What is the main concern?
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Answer C: The wires may hang lower than the top of your vehicle
Overhead space has to be checked like any other space around the vehicle, because wires and cables are often lower than they look from the cab.
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9. You are inspecting the vehicle alone and need to confirm that the stop lights work. Which method is correct?
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Answer A: Have a helper press the brake pedal, or apply the brake in a way that keeps it on while you check from outside
Stop lights are checked from outside the vehicle while the brakes are applied, so a helper or a brake held on is needed.
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10. Why must tiedowns be rechecked during a trip even when they were tight at the start?
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Answer C: Road vibration and cargo movement can loosen them as the miles go by
Straps and chains settle and loosen as the vehicle bounces and the cargo shifts slightly, so the load must be rechecked at the required intervals.
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11. How many vehicles must be registered in a person name before Arizona will consider a certificate of self-insurance?
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Answer C: More than ten
Arizona allows a person with more than ten motor vehicles registered in that name to apply to the director for a certificate of self-insurance or partial self-insurance.
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12. On a multilane highway, which lane should a heavy vehicle normally use?
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Answer A: The right lane, except to pass or where signs direct otherwise
Keeping right leaves the faster lanes free and reduces the number of vehicles that have to move around a slower, heavier vehicle.
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13. You are strapping down a load with sharp metal edges on a flatbed. What should you use?
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Answer D: Edge protection between the strap and the sharp edges so the tiedown is not cut
Sharp edges cut or wear through a strap under tension, so edge protectors are required wherever a tiedown could be damaged.
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14. What is the purpose of an escape ramp on a mountain grade?
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Answer C: To stop a runaway vehicle without injuring the driver
Escape ramps use soft material or a steep upgrade to bring a vehicle with failed brakes to a controlled stop.
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15. Which parts of total stopping distance can a driver shorten simply by staying alert and looking far ahead?
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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.
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16. A tire may be regrooved only when what is true?
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Answer B: It carries a marking from the manufacturer showing that it is regroovable
Only casings built with extra rubber under the tread and marked regroovable by the manufacturer may be cut, because others would be grooved into the belts.
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17. What happens to braking distance when speed is doubled?
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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.
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18. If an intersection has two lanes marked for left turns, which one should a large vehicle use?
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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.
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19. You are backing a tractor-trailer in a straight line and the trailer starts to drift to the left. What is the standard correction?
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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.
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20. At what time of day do drowsy driving crashes occur most often?
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Answer A: Between midnight and 6 a.m.
The body clock makes people sleepiest in the early morning hours, which is when most fatigue-related crashes happen.
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21. You are on a freeway and see brake lights come on in several vehicles far ahead of you. What should you do?
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Answer A: Ease off the accelerator and get ready to slow down
Brake lights well ahead are an early warning that traffic is slowing, and acting on them gives a heavy vehicle the room it needs.
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22. On a one way street or a divided highway, where are the warning devices placed?
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Answer B: About 10 feet, 100 feet and 200 feet back toward the approaching traffic
When traffic can only come from one side, all three devices are spread out behind the vehicle to give approaching drivers a longer warning.
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23. Federal rules require a power unit that is not carrying placarded hazardous materials to have a fire extinguisher with which minimum rating?
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Answer A: One rated 5 B:C or more, or two rated 4 B:C or more each
The minimum is a single unit rated 5 B:C or more, or two units of at least 4 B:C each, which is enough to attack a fuel or electrical fire.
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24. Why does a cracked frame rail or cross member make a vehicle unsafe?
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Answer B: The frame carries the whole load, and a crack can spread until the structure fails
The frame is the backbone that supports the body, the load and the running gear, so a crack in it is a structural failure that grows with every mile.
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25. You need fuel and the canopy over the pumps is low. What is the safe way to handle the clearance?
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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.
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26. Within total stopping distance, what exactly is perception distance?
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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.
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27. The coolant temperature gauge climbs above its normal range on a long grade. What is the correct response?
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Answer C: Stop when it is safe to do so and find the cause before going on
Rising coolant temperature signals a fault such as a lost belt, a leak or a blocked radiator, and continuing can turn a repair into a destroyed engine.
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28. A vehicle carries placards on its front, rear and both sides. What is the main purpose of those placards?
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Answer C: To tell emergency responders and other people what hazard the cargo presents
Placards warn everyone around the vehicle, especially emergency responders, about the kind of hazard the cargo presents.
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29. You are hauling a sealed trailer and have been told in writing not to open it. How does that affect the en route cargo checks?
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Answer C: You do not have to inspect the cargo itself, but the vehicle and weight are still yours
The en route cargo inspection rule does not apply to a driver of a sealed vehicle who has been ordered not to open it, but every other responsibility, including legal weight, remains.
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30. Why does a load of hanging meat in a refrigerated trailer require special care in curves?
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Answer D: The meat swings and has a high center of gravity, which makes the trailer unstable
Hanging meat is heavy, sits high and swings, so the trailer can tip in a curve or on a ramp taken at normal speed.
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31. What should you look for on the electrical wiring in the engine compartment?
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Answer A: Worn, frayed or cracked insulation and loose or corroded connections
Damaged insulation can short a circuit against the frame or engine, which can kill a lamp you depend on or start a fire.
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32. Part of looking well ahead is planning an out. What does that mean?
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Answer B: Keeping an escape path in mind in case traffic stops suddenly
Because a heavy vehicle often cannot stop in time, good drivers continuously note where they could steer if the space ahead closes.
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33. A sign before a long descent shows 6 percent. What does that number tell you?
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Answer A: How steep the grade ahead is
Percent grade is the drop in feet for every hundred feet of road, so the higher the number the faster speed will build and the lower the gear you need.
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34. What do you check about the fire extinguisher during the pre-trip?
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Answer C: That it is securely mounted, charged and that you know how to operate it
An extinguisher must be held in its bracket, show a charged gauge and be understood by the driver, because a fire leaves no time to learn.
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35. Your windshield washer reservoir is empty and rain and road spray are expected. What should you do?
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Answer D: Fill it before the trip, because you need the washers to keep the windshield clear
Wipers alone smear the film of oil and grit thrown up by traffic, so the washers are part of keeping a usable view of the road.
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36. Why must exhaust components be checked for contact with other parts of the vehicle?
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Answer B: Hot exhaust parts touching fuel lines, tires or wiring can start a fire
Exhaust pipes run hot enough to ignite fuel and melt insulation, so they must be kept clear of the fuel system, the tires and the electrical harness.
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37. Which of these counts as a serious traffic violation for a commercial driver license holder?
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Answer C: Speeding 15 miles per hour or more above the limit
Excessive speeding, reckless driving, improper lane changes, following too closely and texting while driving are all serious traffic violations.
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38. A strap runs from an anchor point on one side of the trailer, over the load, and down to an anchor point on the opposite side. How much of its working load limit counts toward the total required?
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Answer C: All of it
A tiedown that is anchored on one side, passes over or around the cargo and is anchored on the other side counts its full working load limit toward the aggregate figure.
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39. Your truck has a backup alarm that sounds whenever reverse is selected. What may a driver rely on it for?
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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.
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40. In hazard perception, what counts as a hazard?
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Answer C: Any road user or condition that could become a danger
A hazard is anything with the potential to create danger, which is why drivers are taught to spot them early rather than react to emergencies.
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41. Within what distance should high beams be lowered at night?
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Answer D: Within about 500 feet of an oncoming vehicle and within about 500 feet of a vehicle you are following
High beams blind other drivers at close range, so they are lowered at roughly the same distance whether the other vehicle is coming toward you or is ahead of you.
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42. What does the gross combination weight rating cover?
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Answer B: The maximum loaded weight of the power unit together with the trailer or trailers it tows
The combination rating takes in the power unit and everything behind it, loaded, as specified by the manufacturer.
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43. With water standing on the road, hydroplaning can begin at speeds as low as what?
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Answer D: 30 mph
When enough water covers the surface, the tires can ride up on it and lose contact at speeds as low as 30 mph.
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44. Why should a large vehicle be accelerated smoothly and gradually?
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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.
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45. Besides slowing down, which technique most reduces the risk of a skid on a snow covered road?
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Answer B: Make every steering, braking and speed change gradual
Traction is limited on snow, and sudden inputs demand more grip than the surface can supply, so smoothness is what keeps the tires attached to the road.
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46. You normally pull an empty trailer, but today the same tractor is loaded to its legal maximum. What changes about getting under way?
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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.
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47. Which situations call for a mirror check in a commercial vehicle?
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Answer A: Every lane change, turn, merge and tight maneuver
Mirrors must be checked regularly and always before, during and after any movement that changes the path of the vehicle.
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48. During the walkaround you notice one tire on an axle is a radial and the tire next to it is bias-ply. What should you do?
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Answer B: Treat it as a defect, because radial and bias-ply tires must not be mixed on the same axle
Radial and bias-ply tires flex and grip differently, so mixing them on one axle makes the vehicle handle unpredictably and is not allowed.
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49. Where on the road are you most likely to find ice in cold weather?
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Answer B: On bridges, overpasses and shaded stretches, which freeze before the rest of the road
Bridges and overpasses lose heat from above and below, and shaded areas get no sun, so they ice over first and stay icy longest.
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50. Under federal safety rules, what must the driver of a commercial vehicle do before starting a trip?
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Answer A: Be satisfied that the vehicle is in safe operating condition
The driver is responsible for inspecting the vehicle and must be satisfied it is in safe operating condition before the trip begins.