Florida FLHSMV CDL General Knowledge Practice Test 5
Test 5 of 5. Pick an answer for each question to see if it is right and why; your score appears at the end. You need 40 correct answers to pass, the same ratio as the real Florida test.
- Questions50
- Correct to pass40
- Passing score80%
- Minimum age18 years
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1. How should the headlamps be checked during the pre-trip inspection?
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Answer A: By switching on both low beam and high beam and confirming each one works outside
Both beams are separate circuits, so each is switched on in turn and confirmed from outside the vehicle where the lamps can actually be seen.
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2. What happens to a Florida commercial driver found with any alcohol at all in the body while driving a commercial vehicle?
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Answer B: The driver is placed out of service for 24 hours
Any alcohol in the body of a commercial driver results in immediate removal from service for 24 hours.
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3. A 40 foot straight truck and a 70 foot tractor-trailer make the same right turn. Which needs more room and why?
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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.
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4. Cargo falls from your trailer and causes a crash behind you. Who is likely to answer for it?
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Answer C: The driver and the carrier, since securing the load on the road is their duty
Whoever loaded the vehicle, the driver and the carrier are responsible for the load being secure while it is on the road.
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5. A fire has started in the vehicle. How should the extinguisher be used?
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Answer B: Stay as far back as the reach of the extinguisher allows, stand upwind, and aim at the base of the fire
Aiming at the base attacks what is actually burning, and staying upwind and well back protects the driver from heat, smoke and the flames themselves.
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6. What is the correct way to test the parking brake before a trip?
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Answer C: With the parking brake set, put the vehicle in a low gear and gently try to move forward
A parking brake that holds against a gentle pull in low gear is working; if the vehicle moves, the brake needs adjustment or repair.
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7. At 55 mph, about how far does a vehicle travel during a typical 3/4 second perception time plus 3/4 second reaction time, before the brakes even begin to work?
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Answer C: About 120 feet
Each 3/4 second at 55 mph covers about 60 feet, so perception and reaction together use up roughly 120 feet before braking starts.
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8. What do the U-bolts on a leaf spring suspension do?
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Answer A: They clamp the spring assembly to the axle so it cannot move
U-bolts hold the spring pack tight against the axle, and a loose or broken U-bolt lets the axle slide out of place under load.
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9. How do you confirm that the coupling is locked before pulling out of the yard?
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Answer D: By locking the trailer brakes and pulling gently forward against them
The tug test loads the coupling in the direction that would pull it apart, so if the jaws are not closed on the kingpin you find out at walking pace.
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10. You pick up a trailer that another driver dropped in the yard. What must you do before pulling it?
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Answer B: Inspect it yourself, because you are responsible for the whole vehicle you drive
Responsibility follows the driver who moves the vehicle, and a trailer that has stood in a yard may have lost air, developed a flat tire or been damaged.
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11. 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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12. A car is following you far too closely. What is the safest response?
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Answer A: Open up more space ahead so you can slow gradually, avoid sudden changes, and do not speed up
Extra room in front lets you slow smoothly instead of braking hard, which is exactly what the driver behind cannot cope with.
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13. When should the horn of a commercial vehicle be used?
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Answer C: Only when it is needed to avoid a crash
An air horn is loud enough to startle other road users, so it is a warning device rather than a way to comment on other drivers.
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14. When should a lower gear be selected for a long downgrade?
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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.
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15. Why should the radio, the fan and other noisy equipment be switched off during a required stop at a railroad crossing?
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Answer C: So that an approaching train can be heard
The rules require the driver to look and listen along the track, and on a double track crossing a passing train can hide a second one, so hearing matters as much as seeing.
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16. Two tires in a dual set have noticeably different diameters. Why is that a problem?
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Answer C: The larger tire carries more than its share of the load and can be overloaded
The taller tire touches the road first and takes most of the weight, so it runs overloaded and hot while the smaller one does little work.
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17. Which lamp must make the rear registration plate legible after dark?
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Answer C: A white lamp that lights the plate
A white license plate lamp is required so the plate can be read at night, and a burned out one is a defect like any other lamp.
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18. You are stopped in a line of traffic behind a car. How much space should you leave in front of you?
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Answer C: Enough to see where the rear tires of that car meet the road
That amount of space lets you pull around the vehicle ahead if it stalls and absorbs some of the shock if you are struck from behind.
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19. Regular mirror checks during a long trip can reveal which developing problem?
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Answer D: Smoke coming from a tire or from a wheel
Overheating tires, wheel bearings and brakes usually show as smoke long before anything appears on the dash, and mirrors are where a driver sees it.
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20. What should be checked about the power steering system in the engine compartment?
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Answer D: That the fluid level is correct and the hoses and pump are not leaking
Losing power steering fluid means losing steering assistance, which can happen suddenly and makes a heavy vehicle very hard to turn.
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21. Why must cargo also be held down against vertical movement and not only against sliding?
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Answer D: Because a load that bounces can jump the blocking and slacken its own tiedowns
Rough road makes an unrestrained article lift; every bounce lets it move a little and works the tiedowns loose until nothing is holding it.
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22. What is the correct order for a basic double clutch upshift?
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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.
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23. What is the best practice when fog is thick enough to hide the road ahead?
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Answer B: Slow down before entering the fog, and if visibility is too poor, pull off into a rest area or truck stop until it improves
The safest choice in heavy fog is not to be driving in it, and if you are already in it your speed has to come down before your visibility does.
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24. 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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25. May a commercial driver use a hand-held phone while stopped at a red light?
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Answer B: No, a stop in traffic still counts as driving
Hand-held use is allowed only when the vehicle has been moved to the side of or off the highway and halted where it can safely remain stopped.
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26. Total stopping distance is made up of which parts?
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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.
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27. When a helper guides you while backing, what should be agreed on before you start?
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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.
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28. You can see a crack in a brake drum that runs across more than half the width of the friction surface. What does this mean?
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Answer C: The drum is defective and must be repaired before the vehicle is driven
Cracks longer than half the width of the friction area mean the drum can break apart under braking heat and must be replaced.
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29. Which combination of warning devices meets the requirement for a stopped commercial vehicle?
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Answer A: Three reflective triangles, or six fusees, or three liquid burning flares
A vehicle may carry three bidirectional reflective triangles, six fusees or three liquid burning flares as its warning devices.
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30. How do you test for leaks in a hydraulic brake system during the pre-trip inspection?
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Answer A: Pump the pedal three times, then hold firm pressure for five seconds and make sure the pedal does not move
If the pedal sinks while you hold pressure, fluid is escaping or air is in the lines, and the vehicle must not be driven until the problem is repaired.
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31. The car in the next lane still has snow covering most of its windows. What should you assume?
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Answer C: That driver cannot see you and may move into your lane
A driver whose view is blocked cannot see the vehicles around, so you should assume you are invisible and stay out of that vehicle path.
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32. How do you avoid the sharp lurch that comes at the very end of a stop in a heavy vehicle?
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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.
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33. What should you do before backing into a space you have not used before?
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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.
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34. Why does a load of live animals need special attention?
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Answer D: The animals move and lean, so the center of gravity shifts and the vehicle can be pushed off balance in a turn
A live load will not stay where it is put, and that movement changes the balance of the vehicle exactly when a curve is loading it most.
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35. What does safe practice require of a commercial driver who wants to eat, drink or read a delivery note?
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Answer B: Handle it before or after driving, not while moving
Anything that takes hands, eyes or attention away from the task belongs outside the driving time, not inside it.
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36. You are taking a tightly curved highway exit ramp in a long combination. Where should the tractor be placed within the lane?
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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.
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37. 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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38. Why should you avoid using your lights to tell a following driver that it is safe to pass you?
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Answer B: You may misjudge the gap and the driver will act on your signal
The manual warns against signaling others to pass, because the responsibility for a head-on crash then rests on a judgment you could easily get wrong.
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39. What are you looking for when you check the hubs and wheel seals during the walkaround?
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Answer B: Leaking oil or grease, which can also contaminate the brake linings
A leaking hub seal starves the bearing of lubricant and the escaping oil or grease can soak the brake linings and cut braking power.
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40. Which vehicle condition makes hydroplaning more likely?
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Answer C: Tires that are worn or underinflated
Tread depth and correct pressure are what let a tire push water aside, so worn or soft tires lift onto the water film at lower speeds.
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41. You find a defect during the pre-trip inspection. What must happen before the vehicle is driven?
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Answer C: It must be repaired, or the vehicle must not be driven
Writing a defect down does not make the vehicle safe; a defect that affects safe operation has to be corrected before the trip starts.
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42. At a rest area you find that the load has shifted although the straps still feel tight. What should you do?
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Answer C: Correct the load before driving on, since a shifted load is no longer secure
Movement means the securement has already failed once, and a load that has shifted can shift again, so it is put right before the vehicle moves.
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43. Which vehicles are most likely to get hung up on a raised railroad crossing?
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Answer A: Low-slung units such as car carriers and lowboys
Vehicles with low ground clearance or a long wheelbase can bottom out on a humped crossing and become stuck on the tracks.
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44. Which winter preparation matters most for keeping the road in view?
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Answer D: Working wipers, washer fluid and a working defroster
Slush and road spray coat the windshield within minutes in winter, so wipers, washer fluid and the defroster are what keep any view at all.
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45. What are you looking for when you check the drive belts in the engine compartment?
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Answer C: That each belt is snug and free of cracks, frays or heavy wear
A loose or cracked belt can break and stop the fan, the water pump or the alternator, which leads quickly to overheating or a dead electrical system.
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46. Where are regrooved, recapped or retreaded tires not allowed on a truck or truck tractor?
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Answer C: On the front steering wheels
Regrooved and retreaded tires are prohibited on the front wheels of a truck or truck tractor because a steering tire blowout is extremely difficult to manage.
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47. 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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48. Why should a long vehicle never swing out to the left before starting a right turn?
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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.
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49. On a two lane road carrying traffic in both directions, where do the three warning devices go?
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Answer C: About 10 feet from the vehicle on the traffic side, 100 feet behind and 100 feet ahead
Traffic can approach from either direction, so one device goes close to the vehicle and one is placed about 100 feet away in each direction.
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50. An automatic transmission is left in its normal drive position as the vehicle rolls down a long grade. What does it tend to do?
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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.