Tennessee TDOSHS CDL General Knowledge Practice Test 1
Test 1 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 Tennessee test.
- Questions50
- Correct to pass40
- Passing score80%
- Minimum age21 years
-
1. After two hours of driving you measure a tire and the pressure reads higher than the cold figure. What should you do?
Show answer
Answer B: Nothing, because pressure rises normally as a tire heats up in use
Air expands as the tire heats, so a higher hot reading is expected, and letting air out leaves the tire underinflated once it cools.
-
2. Which vehicle is most likely to be pushed around by a strong crosswind?
Show answer
Answer B: An empty van trailer
A large flat side with very little weight behind it gives the wind the most surface and the least resistance, which is the empty van trailer.
-
3. Why does extra weight make a long downgrade more dangerous even when the brakes are in good order?
Show answer
Answer B: Gravity adds to the momentum and the brakes heat up faster
The heavier the vehicle, the more energy the brakes must turn into heat, and heat is exactly what makes brakes fade on a long descent.
-
4. The scale shows that your combination is over the legal gross weight. Why will sliding the tandems not fix it?
Show answer
Answer B: Because sliding the axles changes where the weight sits, not how much there is
Repositioning axles redistributes weight between axle groups; when the total is too high, freight has to come off the vehicle.
-
5. In a vehicle with a manual transmission, when should the clutch be pushed in during a normal stop?
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.
-
6. 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.
-
7. Can a Tennessee commercial driver license holder obtain a restricted license to keep operating a Class A, B or C commercial vehicle after a DUI related revocation?
Show answer
Answer B: No, restricted licenses cannot be issued for Class A, B or C commercial credentials
Tennessee flatly excludes Class A, B and C commercial licenses from the restricted license program, so a suspended or revoked CDL holder cannot use that route to keep driving commercially.
-
8. What can repeated violations of the federal phone and texting rules cost a commercial driver?
Show answer
Answer D: Disqualification of the commercial driver license
Multiple convictions for using a hand-held phone or texting while driving a commercial vehicle lead to disqualification, on top of fines for driver and carrier.
-
9. What is the correct way to make a right turn in a long vehicle?
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.
-
10. Which lights should be used in fog, by day or by night?
Show answer
Answer A: Low beams and fog lights, together with the four-way flashers
High beam light bounces back off the water droplets and makes seeing worse, while low beams, fog lights and flashers help you see and help others see you.
-
11. A doctor prescribes you a medicine that can cause drowsiness. What should you do?
Show answer
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.
-
12. You are about to cross a long, high bridge with a light load in gusty wind. What should you do?
Show answer
Answer C: Slow down and be ready for a sudden push
Wind is strongest where a bridge leaves the shelter of the land, and lower speed gives you time to correct when the first gust hits.
-
13. Does the federal texting ban apply to a company dispatching device mounted in the cab?
Show answer
Answer B: Yes, entering or reading text on it while driving is banned
The rule is written around the act of reading or entering text on any electronic device, not around who owns the device.
-
14. You are inspecting the vehicle alone and need to confirm that the stop lights work. Which method is correct?
Show answer
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.
-
15. Why should a long vehicle never swing out to the left before starting a right turn?
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.
-
16. How does bracing differ from blocking when securing cargo?
Show answer
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.
-
17. Where on the road are you most likely to find ice in cold weather?
Show answer
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.
-
18. You have countersteered to correct a rear-wheel skid and the vehicle straightens out. What must you be ready for next?
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.
-
19. An automatic transmission is left in its normal drive position as the vehicle rolls down a long grade. What does it tend to do?
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.
-
20. How is the fluid level in an automatic transmission usually checked?
Show answer
Answer A: With the engine running, following the procedure in the operator manual
Most automatic transmissions are designed to be checked with the engine running, and the operator manual gives the exact conditions for that vehicle.
-
21. Which Tennessee CDL endorsements make it impossible to be excused from carrying a medical card?
Show answer
Answer A: Passenger, school bus and hazardous materials
Tennessee states that no exemption from the medical card is possible for a driver who holds a passenger, school bus or hazardous materials endorsement.
-
22. 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.
-
23. In the seven-step method, what comes immediately after starting the engine and inspecting inside the cab?
Show answer
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.
-
24. At the end of the day you find no defects on a property carrying vehicle. What does the federal rule require?
Show answer
Answer B: No written report is required, although the carrier may still ask for one
For property carrying vehicles the report is required only when a defect or deficiency is found or reported, although a carrier may impose a stricter policy.
-
25. Which clues warn you that a parked car may pull out or open a door?
Show answer
Answer A: Exhaust smoke, turned front wheels, a person in the seat
Signs of life in a parked vehicle, such as a running engine, turned wheels or an occupant, mean it may move or open a door into your path.
-
26. You are hauling livestock and the trailer is only partly full. What should be done?
Show answer
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.
-
27. 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.
-
28. The engine oil pressure gauge falls toward zero while you are driving. What should you do?
Show answer
Answer C: Stop as soon as it is safe to do so and shut the engine down
Loss of oil pressure destroys an engine in a very short time, so the correct response is to stop and shut down rather than to drive on.
-
29. You are backing a tractor-trailer in a straight line and the trailer starts to drift to the left. What is the standard correction?
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.
-
30. During a stop you find a package in the trailer leaking an unknown chemical. What should you do?
Show answer
Answer C: Keep clear, keep others away and get help without touching the package
A driver without the training and equipment does not handle a leak; the job is to protect people from the material and get qualified help to the scene.
-
31. After starting the engine, how quickly should the oil pressure gauge come up to its normal range?
Show answer
Answer B: Within a few seconds
Oil pressure should build within seconds of starting; if it stays low, the engine is not being lubricated and should be shut down.
-
32. On a scale, your loaded truck is well under the gross weight limit, but one axle is above the limit for that axle. What does this mean?
Show answer
Answer D: The vehicle is overloaded and the load must be shifted or reduced before you drive on
Each axle and axle group has its own limit and each must be respected; being under the gross limit does not excuse an overloaded axle.
-
33. What should you do before backing into a space you have not used before?
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.
-
34. You are driving past a park where children are playing close to the curb. What is the correct assumption?
Show answer
Answer A: A child may run into the street without looking
Children act on impulse and do not judge traffic well, so a driver has to expect one to enter the road and slow down in advance.
-
35. How can a driver tell that a shipment includes hazardous materials?
Show answer
Answer B: The shipping paper describes them and the packages carry hazard warning labels
Hazardous materials are identified on the shipping paper with their shipping name and hazard class, and the packages themselves carry labels showing the hazard.
-
36. A straight truck has a long body behind the rear axle. What happens to that overhang in a sharp left turn?
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.
-
37. What is the driver looking for when the exhaust system is inspected?
Show answer
Answer B: Loose, broken or missing pipes, brackets or clamps, and signs that exhaust is leaking
A loose or leaking exhaust system can send carbon monoxide into the cab and can put hot gas against parts that will burn.
-
38. Why should the radiator cap never be removed while the engine is hot?
Show answer
Answer A: The cooling system is under pressure and scalding coolant can be sprayed out
A hot cooling system holds pressurized coolant above its normal boiling point, so releasing the cap can throw boiling liquid and steam at whoever is holding it.
-
39. You are loading lengths of large diameter pipe on a flatbed. What is needed besides the tiedowns?
Show answer
Answer D: Chocks, wedges or cradles that keep the pipe from rolling
Anything that can roll must be prevented from rolling by chocks, wedges, cradles or a similar device that is itself secured so it cannot come out.
-
40. Which road users are hardest to see at night?
Show answer
Answer C: Pedestrians and cyclists in dark clothing
People on foot or on a bicycle carry no lights of their own in many cases, so they appear only when the headlights reach them.
-
41. On the Interstate System, what is the federal maximum weight allowed on a single axle?
Show answer
Answer A: 20,000 pounds
Federal limits for the Interstate System cap one single axle at 20,000 pounds.
-
42. Why is a leaking exhaust system on a commercial vehicle dangerous to the driver?
Show answer
Answer B: It can let carbon monoxide reach the cab, where it can poison the occupants
Exhaust gas contains carbon monoxide, which has no smell and dulls the driver judgment long before it becomes obvious that anything is wrong.
-
43. What happens if a candidate fails to show up for a scheduled CDL skills test at a Tennessee Driver Service Center?
Show answer
Answer B: A 45 day wait applies before rescheduling
Tennessee imposes a 45 day wait before a no-show candidate can reschedule the commercial skills test.
-
44. Part of your load stands high enough to hide a rear lamp or a reflector. What must be done?
Show answer
Answer B: The load must be moved or extra lamps fitted so the required lights can be seen
Required lamps and reflectors must remain visible; if the cargo blocks them, the load is rearranged or additional lamps are fitted so the vehicle can still be seen.
-
45. A fire has started in the vehicle. How should the extinguisher be used?
Show answer
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.
-
46. What information does an inspection decal on a commercial vehicle carry?
Show answer
Answer B: The date of the inspection, where the inspection report is kept, and information identifying the vehicle
The decal shows when the inspection was done, the name and address of the entity that holds the inspection report, and which vehicle it belongs to, so an officer can confirm the inspection at a glance.
-
47. 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.
-
48. What does the suspension system weight rating tell the driver?
Show answer
Answer A: The maximum weight that the manufacturer says the suspension can carry
Like tires and axles, suspensions have a manufacturer capacity, and loading beyond it can damage springs and air bags.
-
49. What does a front-end header board on a van or flatbed protect against?
Show answer
Answer A: Cargo moving forward toward the cab in a crash or hard stop
The header board, often called a headache rack, blocks forward movement of the load toward the driver.
-
50. 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.