Wyoming WYDOT CDL General Knowledge Practice Test 8
- Questions50
- Correct to pass40
- Passing score80%
- Minimum age18 years
-
1. What is the purpose of the header board, or headache rack, that you inspect behind the cab?
Show answer
Answer A: It protects the driver from cargo that shifts forward during a hard stop
In a hard stop the load keeps moving forward, and the header board is the barrier between that load and the back of the cab.
-
2. You are given a ratchet strap with a deep cut along one edge. What should you do?
Show answer
Answer C: Do not use it; a damaged tiedown cannot be relied on to hold its rated load
Cuts, burns, knots and broken stitching weaken a strap far below its marked working load limit, so it must be taken out of service.
-
3. How long must a motor carrier keep a driver vehicle inspection report and the certification of repairs?
Show answer
Answer B: Three months
The original report and the certifications attached to it are kept on file for three months from the date the report was prepared.
-
4. Why should both outside mirrors be checked over and over while backing?
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.
-
5. The shipper hands you the placards for a load that needs them. Who puts them on the vehicle?
Show answer
Answer C: The driver, who must also make sure they are the correct ones and are readable
The shipper supplies the placards, but it is the driver who must place them on the vehicle and confirm that they match the load and can be read.
-
6. Why must you never coast down a hill in neutral or with the clutch pushed in?
Show answer
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.
-
7. Which components on a typical engine are driven by belts that must be checked for wear and tension?
Show answer
Answer D: The alternator, the water pump and, on many vehicles, the air compressor
Belts drive accessories such as the alternator, the water pump and the air compressor, so one failed belt can take out charging, cooling or air supply.
-
8. What are you looking for when you check the hubs and wheel seals during the walkaround?
Show answer
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.
-
9. How long must the record of a periodic inspection be kept?
Show answer
Answer A: Fourteen months
The periodic inspection report is retained for fourteen months from the date of the report, which covers the full twelve month cycle plus a margin.
-
10. While double clutching, what goes wrong if you take too long between the two clutch movements?
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.
-
11. Which vehicles are most likely to get hung up on a raised railroad crossing?
Show answer
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.
-
12. Your load projects more than 4 feet beyond the rear of the vehicle. How must the projecting end be marked?
Show answer
Answer A: With a red or orange flag by day and a red lamp after dark
Federal rules require a warning flag on a rear projecting load in daylight and a red lamp on the end of it when lights are required.
-
13. What is wrong with resting your foot on the clutch pedal between shifts?
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.
-
14. For a modern truck with low-friction parts and a streamlined shape, which gear should be used going down a grade?
Show answer
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.
-
15. You are entering a freeway from a short ramp with a fully loaded trailer. What should you do?
Show answer
Answer A: Begin building speed early and wait for a large gap
A loaded vehicle accelerates slowly, so it needs both a running start and a much larger gap than a car would use.
-
16. During the walkaround you notice a bulge in the sidewall of a trailer tire. What does it indicate?
Show answer
Answer B: Damage inside the tire, which can lead to a sudden failure
A bulge means the internal structure has broken and only the rubber is holding the air, so the tire can burst without warning.
-
17. Which lamp must make the rear registration plate legible after dark?
Show answer
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.
-
18. Federal rules forbid operating a commercial vehicle in which condition?
Show answer
Answer C: In a condition likely to cause a crash or a breakdown
A defect that makes a crash or a breakdown likely has to be corrected before the vehicle is driven, not reported at the end of the trip.
-
19. An angry driver has cut in front of you and is now braking hard to provoke you. What is the safest response?
Show answer
Answer D: Drop back, avoid eye contact and let the driver go
Giving an aggressive driver space and no response removes the conflict, while any answering gesture invites escalation you cannot control in a heavy vehicle.
-
20. What does the federal bridge formula do?
Show answer
Answer C: It reduces the weight allowed on a group of axles as those axles get closer together
Axles bunched together concentrate the load on a short span of a bridge, so the formula lowers the allowable weight as the spacing shrinks.
-
21. Why should water never be used on an electrical fire or a gasoline fire?
Show answer
Answer C: It spreads the fuel and conducts the current
Water carries current back to the person holding the hose and floats burning fuel outward, which is why a B:C rated extinguisher is carried instead.
-
22. 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?
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.
-
23. On packed snow, how much should a commercial driver reduce speed?
Show answer
Answer D: By about one half or more
Packed snow costs far more traction than rain, so speed should be cut by half or more.
-
24. What should the ammeter or voltmeter show once the engine is running?
Show answer
Answer D: A reading in the normal charging range
With the engine running, the alternator should be charging; a discharge reading or an abnormal charge level means an electrical fault.
-
25. What is the payload of a truck?
Show answer
Answer C: The weight of the cargo the vehicle is carrying, that is the loaded weight less the empty weight
Payload is what is left of the legal or rated weight once the weight of the empty vehicle is taken off, and it is the weight of cargo that can be carried.
-
26. What does Wyoming law impose on a CDL holder convicted of serious moving violations such as following too closely or texting while driving a commercial vehicle?
Show answer
Answer B: A 60-day disqualification for two serious violations in a three-year period, and 120 days for a third or subsequent conviction
Under W.S. 31-7-305 two or more serious violations within a three-year period bring a 60-day disqualification, and a third or subsequent conviction brings 120 days.
-
27. When must a driver first inspect the cargo and its securement devices?
Show answer
Answer C: Before starting the trip, as part of the pre-trip inspection
Cargo is part of the pre-trip inspection; the later checks within 50 miles and every three hours or 150 miles come on top of that first inspection.
-
28. An oncoming vehicle at night has bright headlights that are making it hard to see. What should you do?
Show answer
Answer B: Look toward the right edge of your lane and avoid looking directly at the lights
Looking at the right edge of the road keeps your eyes off the glare while you stay in your lane; glare can leave you nearly blind for several seconds.
-
29. Which description matches controlled braking during an emergency stop?
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.
-
30. Which items belong to the trailer part of the walkaround inspection?
Show answer
Answer D: Landing gear, doors, tires, wheels, lights, reflectors, frame and cargo securement
The trailer has its own running gear, lighting, structure and load, and all of it is the responsibility of the driver pulling it.
-
31. 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?
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.
-
32. Why do worn tires lose grip so quickly on a wet road?
Show answer
Answer D: Shallow tread cannot move water out from under the tire
The grooves in a tire exist to channel water away so the rubber can touch the road, and a worn tire has lost that capacity.
-
33. What does gross vehicle weight mean, as opposed to gross vehicle weight rating?
Show answer
Answer B: The actual weight of the single vehicle plus everything it is carrying
Gross vehicle weight is what the vehicle actually weighs at that moment; the rating is the maximum the manufacturer allows it to weigh.
-
34. Why must exhaust components be checked for contact with other parts of the vehicle?
Show answer
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.
-
35. Cargo securement must be strong enough to hold the load under which conditions?
Show answer
Answer A: Hard braking, hard acceleration and hard turning, as well as the bouncing of the road
The securement standard is written around the forces of a hard stop, a hard start, a hard turn and vertical movement on a rough surface, all of which occur in ordinary driving.
-
36. You are hauling a load of steel plate that is well within every weight limit but is stacked five feet high on a flatbed. What is the main concern?
Show answer
Answer A: The center of gravity is high, so the rig will roll more easily in a curve
Legal weight does not make a load safe; height raises the center of gravity and it is height, not weight alone, that decides how readily the vehicle rolls over.
-
37. Under the federal air brake standard, the low air pressure warning must come on before reservoir pressure drops below what level?
Show answer
Answer A: Before pressure falls below 60 psi
Federal Motor Vehicle Safety Standard 121 requires the warning to operate while service reservoir pressure is still above 60 psi, which leaves enough air to bring the vehicle to a normal stop.
-
38. When should a driver add space beyond the basic following distance rule?
Show answer
Answer D: On slippery roads and whenever visibility is poor
The seconds rule is a minimum for good conditions, so rain, snow, darkness and heavy traffic all call for more space than that.
-
39. Why does a heavy vehicle need a much larger gap than a car in order to cross or enter traffic?
Show answer
Answer C: Because it accelerates slowly and needs far more road and time to clear the intersection
Slow acceleration combined with the length of the vehicle means a gap that would feel comfortable in a car is nowhere near enough.
-
40. What must the driver confirm about the required emergency equipment before a trip?
Show answer
Answer A: That it is in place, in working order and ready to be used
Federal rules require the driver to be satisfied that the emergency equipment is present and ready, because it is needed at the worst possible moment.
-
41. An unblocked article is 8 feet long and weighs 900 pounds. How many tiedowns does the federal rule require?
Show answer
Answer B: Two
Only an article that is 5 feet or shorter and 1,100 pounds or lighter can be held with a single tiedown; anything longer than 5 feet needs at least two whatever it weighs.
-
42. What is the most common cause of a front-wheel skid, where the vehicle keeps going straight even though you turn the wheel?
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.
-
43. You have chosen 40 miles per hour as your safe speed for a downgrade. How should the brakes be used?
Show answer
Answer A: Brake firmly to about 35, release, and repeat at 40
Proper technique is firm application to about 5 miles per hour below the safe speed, then full release so the brakes cool before the next application.
-
44. With the tractor coupled to the trailer, what should you see between the upper and lower fifth wheel plates?
Show answer
Answer A: No space at all between the two plates
Any daylight between the plates means the trailer is not properly seated on the fifth wheel and the coupling can come apart under load.
-
45. When should a lower gear be selected for a long downgrade?
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.
-
46. The coolant temperature gauge climbs above its normal range on a long grade. What is the correct response?
Show answer
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.
-
47. You have a part load that fills only a third of a long trailer. How should it be placed?
Show answer
Answer C: Spread out and centerd side to side, so the weight sits over the axles
A part load is spread over as much of the floor as possible and kept centerd, so no axle is overloaded and the vehicle stays balanced from side to side.
-
48. What are you checking when you pull the engine oil dipstick during the pre-trip?
Show answer
Answer A: That the oil level is within the safe operating range marked on the stick
The dipstick shows whether there is enough oil to lubricate and cool the engine, and a level outside the safe range must be corrected before driving.
-
49. Your drive wheels start to spin and the rear begins to slide while you accelerate on a slick surface. What should you do?
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.
-
50. What does the tachometer on the dashboard of a heavy truck show?
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.