South Dakota DPS 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 South Dakota test.
- Questions50
- Correct to pass40
- Passing score80%
- Minimum age18 years
-
1. Why must the driver of a large vehicle keep it centered in its lane?
Show answer
Answer B: The vehicle needs the full width of the lane
A commercial vehicle is close to lane width already, so any drift takes part of the vehicle into the next lane or onto the shoulder.
-
2. Where is a dunnage bag used and how does it work?
Show answer
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.
-
3. You are loading a flatbed that has no sides or bulkheads. How must the cargo be held?
Show answer
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.
-
4. 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.
-
5. 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.
-
6. After starting a trip, when must a driver first re-inspect the cargo and the devices holding it?
Show answer
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.
-
7. 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.
-
8. How long must a South Dakota applicant drive on a CDL instruction permit before taking the skills test?
Show answer
Answer B: 14 days
South Dakota requires the applicant to drive on a CDL instruction permit for 14 days before taking the skills test at a third party testing site.
-
9. 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.
-
10. You are about to slow down sharply on a highway to make a turn into a narrow driveway. How can you warn the drivers behind you?
Show answer
Answer C: Tap the brake pedal a few times so the brake lights flash before you slow down
A few light taps flash the brake lights and give following drivers an early warning that you are about to slow or stop.
-
11. What does safe practice require of a commercial driver who wants to eat, drink or read a delivery note?
Show answer
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.
-
12. Besides the hours when the law requires them, when should headlights be switched on?
Show answer
Answer A: Any time visibility is poor, such as in rain, fog or at dusk
Headlights are used to be seen as much as to see, so they belong on whenever light or weather makes the vehicle harder to spot.
-
13. How does South Dakota extend the one-year CDL disqualification offenses when the violation happens while transporting placarded hazardous materials?
Show answer
Answer D: The disqualification period increases to three years
When a listed disqualifying offense occurs while the driver is hauling placarded hazardous material, the one-year disqualification becomes three years.
-
14. You must steer hard around an obstacle at highway speed. What is the correct technique?
Show answer
Answer B: Avoid braking while turning, turn only as far as needed, and countersteer as soon as the obstacle is passed
Braking during a hard steering input can lock the wheels and start a skid, and turning back at once keeps the vehicle from running off the far side of the road.
-
15. A 60 foot combination traveling above 40 mph should hold how many seconds of following distance?
Show answer
Answer D: Seven seconds
Six seconds cover the 60 feet of vehicle length, and one extra second is added because the speed is above 40 mph.
-
16. 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.
-
17. How should the headlamps be checked during the pre-trip inspection?
Show answer
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.
-
18. What is the purpose of blocking placed against cargo on a trailer deck?
Show answer
Answer B: To fill the space around the cargo so it cannot slide
Blocking is shaped to fit snugly against the cargo and fastened to the deck, removing the room the load would need in order to move.
-
19. Under the federal hours of service rules, how long may a property-carrying driver drive after 10 consecutive hours off duty?
Show answer
Answer D: Up to 11 hours, and only within a 14 hour window that starts when the driver comes on duty
The federal limit is 11 hours of driving after 10 consecutive hours off duty, and all of that driving has to fall inside a 14 hour window.
-
20. When must a post-trip inspection be made?
Show answer
Answer D: At the end of each day the driver operates the vehicle
The post-trip inspection closes out each driving day so that anything found is recorded before the vehicle is handed to the next driver.
-
21. You are strapping down a load with sharp metal edges on a flatbed. What should you use?
Show answer
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.
-
22. You are backing with a helper guiding you and the helper drops out of sight in your mirror. What should you do?
Show answer
Answer B: Stop until you can see the helper again
If you cannot see the helper you cannot receive a signal to stop, so the only safe action is to halt until visual contact is restored.
-
23. 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.
-
24. What happens to braking performance if oil or grease reaches a brake lining?
Show answer
Answer B: That brake loses much of its effect and the vehicle can pull to one side
A contaminated lining cannot grip the drum, so that wheel contributes little braking and the vehicle pulls toward the side that is still working.
-
25. A South Dakota CDL holder is convicted of a traffic violation in another state. What must the driver do?
Show answer
Answer B: Notify the Department of Public Safety within 30 days of the conviction
A South Dakota CDL or commercial learner's permit holder must notify the department within 30 days of any conviction for a motor vehicle traffic violation other than parking, wherever it happened.
-
26. How far ahead can a driver see with low beams and with high beams?
Show answer
Answer C: About 250 feet with low beams and about 350 to 500 feet with high beams
Low beams reach roughly 250 feet and high beams roughly 350 to 500 feet, and speed at night has to stay inside the distance the lights really show.
-
27. Which of these counts as a serious traffic violation for a commercial driver license holder?
Show answer
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.
-
28. Cargo falls from your trailer and causes a crash behind you. Who is likely to answer for it?
Show answer
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.
-
29. Federal rules say a commercial vehicle may not be driven unless what is true of its cargo?
Show answer
Answer B: It is properly distributed and adequately secured
The basic federal requirement is that the load be distributed properly and secured well enough that it cannot move, whatever the paperwork says.
-
30. What is the minimum age to obtain a South Dakota commercial driver license?
Show answer
Answer C: 18 years old
The Department of Public Safety requires every South Dakota CDL applicant to be at least 18 and to pass the general knowledge test, any specialized tests and a skills test.
-
31. You are moving an oversized load under a permit that requires a pilot vehicle. What is the pilot vehicle there to do?
Show answer
Answer B: Warn other traffic and check the route ahead for clearances and hazards
Escort or pilot vehicles warn approaching traffic and scout the route for low bridges, narrow spots and other hazards that a wide or long load cannot pass.
-
32. What extinguisher rating is required on a vehicle carrying hazardous materials in amounts that need placards?
Show answer
Answer B: 10 B:C or more
Placarded loads carry a much higher fire risk, so the required extinguisher rating rises to at least 10 B:C.
-
33. What is checked in step six of the seven-step method?
Show answer
Answer D: The turn signals and the stop lights, checked from outside the vehicle
Step six returns to the cab to switch on the signal and stop lamps, then checks each one from outside, because those lamps are not lit during the earlier light check.
-
34. Why must the downshift be finished before you reach a steep downgrade or a sharp curve rather than during it?
Show answer
Answer D: Because once your speed is too high you may not get into any gear at all
If you wait until speed has built up, the lower gear may refuse to engage and you can be left in neutral with no engine braking at all.
-
35. While you are driving, what should you do to catch a developing problem with the vehicle?
Show answer
Answer A: Check the gauges regularly and pay attention to unusual sounds, smells or vibrations
Inspection continues during the trip: gauges, mirrors and your senses can reveal a problem long before a warning light does.
-
36. You are pulling a loaded pneumatic dry bulk trailer and approach an exit ramp posted at 35 mph. What is the safest approach?
Show answer
Answer C: Slow to well below the posted speed before the ramp begins
A dry bulk trailer carries its weight high and the load can move, so the ramp speed posted for a car is far too fast and the slowing must be finished before the curve.
-
37. What should you check about the tire valve stems during the walkaround?
Show answer
Answer D: That the stems are not cut, cracked or leaking and the caps are in place
A split stem or a missing cap lets air escape or lets dirt into the valve, and either one can flatten a tire between stops.
-
38. An enforcement officer inspects your vehicle at the roadside and attaches an out-of-service sticker. What may you do?
Show answer
Answer C: Nothing until the defect is repaired; the vehicle may not be driven
An out-of-service order means the vehicle is unsafe, and no schedule, load or destination allows it to be driven before the defect is corrected.
-
39. Which combination of warning devices meets the requirement for a stopped commercial vehicle?
Show answer
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.
-
40. 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.
-
41. Which step of the seven-step inspection method comes immediately after checking the engine compartment?
Show answer
Answer D: Start the engine and inspect the inside of the cab
Once the hood is closed the driver moves to the driver seat, starts the engine and checks gauges, controls and warning devices before going any further.
-
42. Where are the OVERSIZE LOAD signs normally carried on a vehicle moving under such a permit?
Show answer
Answer A: On the front and the rear of the vehicle
The warning signs face the traffic that meets the load and the traffic that comes up behind it, so they go on the front and the rear.
-
43. What is checked about the engine cooling system during the engine compartment inspection?
Show answer
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.
-
44. What does South Dakota law require of the vehicles that must stop at railroad crossings, regarding how they cross the tracks afterward?
Show answer
Answer C: They must cross in a gear that avoids the need to shift gears while on the tracks
After stopping, these vehicles must cross using a gear that will not require a gear change while traversing the tracks.
-
45. What are you checking when you look at the batteries during the engine compartment inspection?
Show answer
Answer D: That they are securely mounted, the connections are tight and free of corrosion, and the caps are in place
Loose or corroded batteries can fail or short out, so the mount, cables, terminals and vent caps are all part of the check.
-
46. At what time of day do drowsy driving crashes occur most often?
Show answer
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.
-
47. What must the motor carrier do about a defect listed on a driver vehicle inspection report?
Show answer
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.
-
48. In dense city traffic you cannot see 12 seconds ahead because other vehicles block the view. What is the best response?
Show answer
Answer A: Slow down and open up more space in front of you
When you cannot see far enough ahead, extra following distance buys back the reaction time that the blocked view has taken away.
-
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.