Oregon DMV CDL General Knowledge Practice Test 4
Test 4 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 Oregon test.
- Questions50
- Correct to pass40
- Passing score80%
- Minimum age18 years
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1. 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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2. Where is a dunnage bag used and how does it work?
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Answer D: Between pieces of cargo inside a van, where it is inflated to take up the gap
A dunnage bag is placed in the void between loads and inflated so the cargo is wedged and cannot move as the vehicle rolls and brakes.
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3. You are given a ratchet strap with a deep cut along one edge. What should you do?
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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.
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4. How does a typical escape ramp stop a runaway vehicle?
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Answer B: With a bed of loose gravel or sand, often on an upgrade
Escape ramps use deep loose material, usually combined with a rising grade, so the vehicle is slowed gradually instead of being stopped by impact.
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5. Why must you never coast down a hill in neutral or with the clutch pushed in?
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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.
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6. Besides staying secure, cargo carried inside a vehicle must not do what?
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Answer C: Block the driver view or access to emergency equipment and exits
Cargo may not obstruct the view to the front or sides or prevent the driver from reaching emergency equipment and exits.
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7. How often must every commercial motor vehicle receive a periodic inspection?
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Answer C: At least once every twelve months
Federal rules require each commercial motor vehicle to pass a periodic inspection at least once in every twelve month period.
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8. If a CDL holder's alcohol-related offense occurs while operating a CMV placarded for hazardous materials in Oregon, the minimum disqualification period increases to what?
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Answer C: 3 years
Oregon's CDL manual raises the minimum disqualification from one year to three years when a qualifying alcohol or drug offense occurs while the CMV is placarded for hazardous materials.
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9. You must leave the vehicle parked on a slight grade. What adds security beyond setting the parking brake?
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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.
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10. What is the danger of letting engine speed climb past the top of the rated rpm range before you shift?
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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.
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11. 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.
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12. A straight truck has a long body behind the rear axle. What happens to that overhang in a sharp left turn?
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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.
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13. During the vehicle overview, what should the driver look for on the ground under the vehicle?
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Answer B: Fresh puddles of oil, coolant, grease or fuel
New stains on the ground are the earliest sign of a leak, so the overview includes a look underneath before anything is opened or started.
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14. Who must provide entry level driver training for a first time Oregon Class A or Class B CDL applicant?
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Answer A: A school or entity listed on the FMCSA Training Provider Registry
Oregon requires entry level driver training from a school or other entity listed on the FMCSA Training Provider Registry for first time Class A and Class B applicants and for first time passenger, school bus and hazardous materials endorsements.
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15. You are pulling away from the curb after a delivery. Why is a mirror check needed first?
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Answer B: A cyclist or a vehicle may be coming up alongside you
Traffic and cyclists can arrive alongside a parked vehicle at any moment, so the mirrors must be checked immediately before pulling out.
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16. 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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17. Which description matches controlled braking during an emergency stop?
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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.
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18. What is axle weight?
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Answer C: The weight carried to the ground by one axle or one set of axles
Axle weight describes how the load is shared among the axles that carry it to the road, not how much the whole vehicle weighs.
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19. Which of these is NOT on the federal list of parts and accessories the driver must be satisfied are in good working order before driving?
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Answer D: The seat cushion upholstery
The federal pre-trip rule names brakes, steering, lights and reflectors, tires, horn, wipers, mirrors, coupling devices, wheels and rims, and emergency equipment; seat upholstery is not on that list.
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20. Where on a tire is tread depth measured?
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Answer C: In a major tread groove, away from any tie bar or wear indicator
Depth is taken in a major groove and away from the raised tie bars and wear indicators, which would give a shallower and misleading reading.
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21. What is the basic rule about backing a large vehicle?
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Answer B: Avoid backing whenever there is another way
Backing is dangerous because you cannot see everything behind you, so the manual tells drivers to plan routes and parking that avoid it.
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22. How long do Oregon commercial knowledge test results remain valid?
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Answer C: 6 months
Oregon keeps commercial knowledge test results valid for six months from the date the test is passed; after that the applicant must test again.
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23. What must the motor carrier do about a defect listed on a driver vehicle inspection report?
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Answer D: Repair it, or certify that repair is not needed, before the vehicle is dispatched again
A reported defect must be corrected, or certified as not needing correction, and that certification is what the next driver reads before taking the vehicle.
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24. 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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25. 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?
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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.
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26. After starting a trip, when must a driver first re-inspect the cargo and the devices holding it?
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Answer A: Within the first 50 miles
Federal rules require a check of the load and its securement within the first 50 miles, because settling and vibration loosen straps and chains early in a trip.
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27. 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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28. 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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29. Which components on a typical engine are driven by belts that must be checked for wear and tension?
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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.
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30. What does gross vehicle weight mean, as opposed to gross vehicle weight rating?
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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.
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31. What does the driver check in the final step of the seven-step inspection?
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Answer A: Hydraulic brake leaks where those brakes are fitted, then the parking brake and the service brakes
The last step is done with the engine started: test for hydraulic leaks on vehicles with hydraulic brakes, then prove that the parking brake holds and that the service brakes stop the vehicle.
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32. You press on a drive belt and it deflects far more than the others. What does that suggest?
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Answer C: The belt is too loose and the part it drives may not work properly
A belt with excessive play slips on its pulleys, so the accessory it drives turns too slowly or not at all under load.
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33. You are hauling an open box of loose gravel. What does that load require?
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Answer A: A cover, so that material cannot blow off or spill onto the road
Loose material that can be blown or spilled has to be covered so it does not come out of the body and strike traffic behind.
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34. Where do you find the maximum weight a tire can safely carry?
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Answer D: Stamped on the sidewall of the tire itself
Each tire is marked with the greatest weight it can carry at a stated inflation pressure, and the load on an axle must stay within the total for its tires.
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35. Why should high beams not be used in fog?
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Answer A: The light reflects back off the droplets and blinds you
Fog is made of water droplets that scatter light straight back at the driver, so a stronger beam makes the wall of glare worse rather than better.
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36. How does bracing differ from blocking when securing cargo?
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Answer B: Bracing runs from the upper part of the cargo to the floor or walls to keep it from moving, while blocking fits snugly against the cargo
Blocking is shaped to fit against the front, back or sides of a piece of cargo; bracing supports it from above so it cannot tip or shift.
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37. How does a driver measure following distance in seconds?
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Answer A: Wait for the vehicle ahead to pass a fixed roadside object, then count the seconds until the front of your vehicle reaches the same object
Counting from the moment the vehicle ahead passes a landmark until you reach it turns a gap you cannot judge in feet into a number of seconds.
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38. You are loading a flatbed that has no sides or bulkheads. How must the cargo be held?
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Answer D: By tiedowns, blocking or bracing, since there are no walls to keep it from shifting or falling off
Open decks depend entirely on securement devices; every article must be tied down or otherwise immobilized so it cannot move, spill or fall.
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39. What does the gross vehicle weight rating of a vehicle describe?
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Answer A: The maximum loaded weight of that single vehicle, as specified by the manufacturer
The rating is the manufacturer figure for the loaded weight of one vehicle, so it is a limit fixed in advance rather than a measurement of the load on board today.
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40. What is checked about the engine cooling system during the engine compartment inspection?
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Answer C: That the coolant level is adequate and the radiator and hoses are not leaking
A low coolant level or a leaking hose leads to overheating, which can stop the vehicle in a place where stopping is dangerous.
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41. At highway speed, looking 12 to 15 seconds ahead means looking about how far down the road?
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Answer B: About a quarter of a mile
Twelve to fifteen seconds of travel is roughly a quarter of a mile at highway speed, while the same amount of time is about one block in slow city traffic.
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42. Why is it harder to judge speed and distance at night?
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Answer C: You see much less detail and have fewer reference points
Darkness removes the visual references that the brain uses to estimate distance and closing speed, so drivers routinely misjudge both.
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43. In the seven-step method, what comes immediately after starting the engine and inspecting inside the cab?
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Answer D: Turn off the engine and check the lights
Step four shuts the engine down and switches on the lamps needed for driving so the driver can leave the cab and confirm they actually work.
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44. 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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45. A CDL holder found to have any detectable amount of alcohol below the illegal 0.04 percent threshold while operating a CMV in Oregon faces what consequence?
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Answer B: An out-of-service order for 24 hours
Even below the 0.04 percent illegal threshold, Oregon's CDL rules require any CMV driver with detectable alcohol in their system to be placed out of service for 24 hours.
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46. 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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47. What blood alcohol concentration makes it illegal to operate a commercial motor vehicle under Oregon's CDL rules?
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Answer D: 0.04 percent or more
Oregon's Commercial Driver Manual sets the illegal threshold for operating a CMV at a blood alcohol concentration of 0.04 percent or more.
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48. A doctor prescribes you a medicine that can cause drowsiness. What should you do?
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Answer A: Tell the doctor what you drive and not drive while affected
Both prescription and over the counter medicines can make a driver unsafe, so the medical professional must know the job and the driver must stay out of the seat while affected.
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49. When should a driver add space beyond the basic following distance rule?
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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.
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50. You are hauling livestock and the trailer is only partly full. What should be done?
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Answer A: Use false bulkheads or partitions to keep the animals bunched together
Animals that can move around shift the center of gravity, so a partial load is bunched together with partitions to limit how far the weight can move.