GENERAL KNOWLEDGE
KEY FACTS
There is a federal requirement that each state must have minimum standards for the licensing of commercial drivers.
You will have to take 1 or more knowledge test depending on what class of license and endorsements you need.
All applicants take a general knowledge test. This section contains information on safe driving and general information
that all commercial drivers should know. Subjects include inspections of equipment, safety, and driving skills while
on the road.
1. There are three types of vehicle inspections: pre-trip, enroute,
and after-trip (also called post-trip).
23. A driver should be looking 12-15 seconds or about a quarter
mile ahead.
2. Items inspected enroute should include tires, brakes and cargo
securement.
24. When passing, tap your horn, assume the other driver doesn’t
see you and drive to avoid a crash.
3. Mismatched tire size should not be used on the same vehicle.
25. Headlights should be on whenever visibility is reduced.
4. Radial and bias ply tires should not be used on the same
vehicle.
26. Drivers should flash their brake lights to warn others when
you must slow down or stop for something ahead.
5. Brake shoes, pads, or drums should not have oil, grease or
brake fluid on them.
27. Warning devices are placed 10 feet, 100 feet and 200 feet to
the rear on a four lane divided highway.
6.
If one fourth of a leaf spring is missing or broken it’s illegal to
drive the vehicle.
28. When you are broken down, if a hill or curve prevents other
drivers from being able to see you, move the rearmost triangle
500 feet back.
7.
One leaf of a spring, broken or missing is enough to make a
vehicle dangerous.
8. Steering wheels are not allowed to have more than ten degrees
of play.
9. If there are exhaust leaks or steering fluid leaks they should be
fixed before driving.
10. Required emergency equipment includes a fire extinguisher,
warning devices, and spare electrical fuses.
11. Inspection under the hood includes oil level, the condition of
the belts and hoses and damaged electrical wiring.
12. Rough acceleration causes mechanical damage.
13. When starting out on an uphill grade, keep the vehicle from
rolling back by using the parking brake.
14. Backing is always dangerous. It should be done towards the
drivers side and use a helper, if possible.
15. Keep both hands on the steering wheel on opposite sides.
16. Use mirrors to check on tires, other traffic when merging and
the trailer in turns.
17. Remember there are blind spots that a mirror can’t show.
18. Tachometers can be used to help with shifting and double
clutching.
19. Turn signals should be used early.
29. When setting out warning devices, keep them between you
and traffic.
30. Use the air horn only when necessary, it startles other
drivers.
31. A heavy vehicle going 55 mph on dry pavement needs the
length of a football field, or 300 feet, to stop.
32. The heavier a vehicle and the faster it is going, the greater
the stopping distance.
33. Hydroplaning can occur at any speed.
thin tire tread or low air pressure.
It is more likely with
34. On slippery roads, slow down gradually. If on ice, stop as
soon as it is safe.
35. On wet roads reduce speed by one third or snow by one
half.
36. On slippery roads it takes longer to stop and is harder to turn
without skidding, therefore turn and slow down as gently as
possible.
37. When in traffic, driving the same speed as traffic is the safest,
if not an illegal speed.
38. At 35 mph a 40 foot vehicle needs 4 seconds space between
it and the vehicle ahead, under good conditions.
39. A vehicle’s height changes with the weight of its load.
40. When being tailgated you should increase your following
distance.
20. Down shift before entering curves.
21. Retarders are to slow the vehicle and reduce brake wear.
22. If traction is poor, a retarder can cause skidding.
41. When turning right from a two-lane street to another two-lane
street, turn wide as you complete the turn.
42. When turning left from one two-lane street to another twolane street, begin turning half way though the intersection.
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GENERAL KNOWLEDGE KEY FACTS con’t
43. If there are two left turn lanes use the one on the right, to
keep traffic on your left side.
65. If the wheels are skidding when braking, you can not control
the vehicle.
44. When entering crossing traffic, remember how large a gap is
needed for a heavy vehicle.
66. Counter steering is turning the wheel back in the other
direction after steering to avoid an emergency.
45. High beams should be used when safe and legal to do so.
67. If the brake pedal goes to the floor with hydraulic brakes,
pump the pedal to try and bring the pressure back up.
46. Drive slowly enough at night to stop within range or your
headlights.
47. When driving in cold weather check tires every two hours or
100 miles.
68. If a tire blows out, stay off the brake, until you have slowed
down.
69. If a rear wheel slips during acceleration let off the throttle.
48. When driving in hot weather check tires every two hours or
100 miles.
70. A vehicle can skid if turned too sharply, over accelerated, or
there is not enough weight on the front axle.
49. Never remove a hot radiator cap.
71. A drive-wheel braking skid can be corrected by stopping the
braking, turning quickly, and counter steering if needed.
50. In hot weather be extra careful of oil level, fan belt tightness,
and avoid high speeds.
51. To dry out wet brakes, apply gentle brake pressure for a short
distance while driving.
72. In a front wheel skid a vehicle tends to move in a straight
direction even if the wheels are turned.
52. Brake fade is usually generally caused by hot brakes.
73. At an accident scene keep the injured warm, stop heavy
bleeding, move them if there is danger of fire or passing traffic.
Don’t give first aid that you are not qualified to give.
53. When going down long downhill grades, use a light steady
pressure on the brakes.
74. Truck fires can be started by under inflated tires, loose fuel
connections or electrical shorts.
54. Newer trucks should go down long downhill grades in a gear
lower than they came up.
75. Water won’t put out an electrical fire or gasoline fire.
55. Escape ramps are designed to prevent damage to the
vehicle.
56. When driving in work zones, slow down, use your flashers,
and warn drivers behind you with your brake lights.
57. When using a curved downhill exit ramp slow down before the
curve.
58. A red triangle with an orange center marks a slow moving
vehicle.
59. In an emergency, you can almost always turn quicker than
you can stop.
60. If you leave the road, avoid braking until your speed is under
20 mph.
61. When steering to avoid a crash, turn no more than is needed
to clear what is in your way and do not apply the brakes when
turning.
62. If an on-coming driver drifts into your lane steer to the
right.
63. Controlled braking is used to keep a vehicle in a straight
line.
64. If you run onto the shoulder, try to stop before coming back
on the highway.
76. A:B:C fire extinguishers can be used on electrical fires, burning
liquids, and burning cloth.
77. All CDL drivers should be able to recognize hazardous cargo,
and whether a HazMat endorsement is required to haul any
one of the nine classes of HazMat.
78. As part of a pre-trip inspection, drivers must check all gauges
including: oil pressure, water temperature, alternator/
voltmeter, air pressure, and oil temperature (if equipped).
79. Most vehicles with manual transmissions require double
clutching to change gears. Do this by slightly pushing the
clutch in 2 quick times while moving the shift lever into and
out of gear.
80. Anti-lock Braking Systems sense when the wheels are about to
lock up during hard brake applications. They are an addition
to your normal brakes. If you have ABS, DO NOT pump your
brake pedal when skidding - let the system do the work for
you and simply apply and hold the pedal down.
81. When a driver doubles their speed in a heavy vehicle, the truck
will take four times as much distance to stop and can cause
four times the destruction.
82. Remember that it takes a typical tractor-trailer unit at least 14
seconds to clear a single railroad track. Never shift gears while
crossing railroad tracks.44. When entering crossing traffic,
remember how large a gap is needed for a heavy vehicle.
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