1 / 25
A. tilted up toward the rear of the tractor.
B. level with the ground.
C. tilted down toward the rear of the tractor.
Check if fifth wheel is in proper position for coupling: The fifth wheel should be tilted down toward rear of tractor.
2 / 25
A. There is enough clearance between the tops of the tractor tires and the nose of the trailer
B. There is enough clearance between the tractor frame and the landing gear
C. Both answers are correct
Check for enough clearance between rear of tractor frame and landing gear and between the top of the tractor tires and the nose of the trailer.
3 / 25
A. The electrical service cable
B. The emergency and service air lines
C. Nothing; back up and lock the fifth wheel
Check glad hand seals and connect tractor emergency and service air-line to trailer emergency and service glad hand. Make sure air-lines are safely supported where they won't be crushed or caught while tractor is backing under the trailer.
4 / 25
A. Trailer brakes are locked
B. Air brakes are off
C. Tractor protection valve is normal
Pull out the air supply knob or move the tractor protection valve control from normal to emergency.
5 / 25
A. The rear wheels of the last trailer
B. The rear wheels of the tractor
C. The rear wheels of the first trailer
If there is more than one trailer, the rear wheels of the last trailer will off-track the most
6 / 25
A. When making a quick lane change or sudden movement of the steering wheel, the tractor tends to rock and sway. The velocity of the rearmost trailer forces the tractor to roll over before the trailer.
B. When making a quick lane change or sudden movement of the steering wheel, the rear trailer tends to swing out. The force of the rear trailer becomes amplified, causing it to roll over.
C. The trailer is half full, and the cargo is loaded in the front of the trailer. When making a sudden movement of the steering wheel, the cargo will tend to forcefully slide to the back of the trailer, forcing the trailer to roll over.
Trucks with trailers have a dangerous crack-the-whip effect caused by rearward amplification. When you make a quick lane change, the crack-the-whip effect can turn the trailer over. There are many accidents where only the trailer has overturned.
7 / 25
A. step on and off the brake pedal several times.
B. flash your high-beam headlights on and off several times.
C. keep pressing the brake pedal firmly.
’s specification usually 20 – 45 psi. This will cause the spring brakes to come on.
8 / 25
A. A 5-axle tractor towing a 45-foot trailer
B. A 5-axle tractor towing a 52-foot trailer
C. A 5-axle tractor towing a 42-foot trailer
When a vehicle goes around a corner the rear wheels follow a different path than the front wheels, and this is called off-tracking or "cheating." Longer vehicles will off-track more. If there is more than one trailer, the rear wheels of the last trailer will off-track the most.
9 / 25
A. speed.
B. rollovers.
C. following too closely.
More than half of truck driver deaths in crashes are the result of truck rollovers.
10 / 25
A. red flags
B. red lights
C. a red flag
According to federal regulations, if the load projects more than 4 feet behind the rear of the vehicle, the end of the load must be marked as follows: (1) with red flags, each 18 inches square, in the daytime; or (2) with two red lights at night.
11 / 25
A. It results in less skidding than using the brake pedal alone
B. It is the best way to brake and keep the truck in a straight line
C. It should not be done
The trailer hand valve, also called the trolley valve or Johnson bar, works the trailer brakes. The trailer hand valve should be used only to test the trailer brakes. Do not use it in driving because of the danger of making the trailer skid.
12 / 25
A. Between 60 and 80 PSI
B. Half the maximum pressure
C. At normal pressure
Make sure air pressure is up to normal.
13 / 25
A. Turning on the parking brakes from the cab
B. Applying and releasing the trailer brakes and listening for brake sounds
C. Lifting the brake pedal
Wait until the air pressure is normal, then shut engine off so you can hear the brakes. Check brake system for crossed air-lines by: applying and releasing trailer brakes and listen for sound of trailer brakes being applied and released. You should hear the brakes move when applied and air escape when the brakes are released.
14 / 25
A. If you must cross into the oncoming lane to make a turn and you see vehicles coming toward you, stop and back up for them.
B. You should turn wide as you complete the turn.
C. You should turn wide before you start the turn.
If you are driving a truck or bus that cannot make the right turn without swinging into another lane, turn wide as you complete the turn. Keep the rear of your vehicle close to the curb. This will stop other drivers from passing you on the right.
15 / 25
A. Brake the vehicle on a slippery road and see if the wheels lock.
B. Look under the vehicle for the ECU and wheel speed sensor wires coming from the back of the brakes.
C. Look under the vehicle for the ABS test light.
It may be difficult to tell if some units are equipped with ABS. Look under the vehicle for the electronic control unit (ECU) and wheel speed sensor wires coming from the back of the brakes.
16 / 25
A. Air lines that control the emergency brakes on combination vehicles
B. Air lines that control the emergency brakes of the tractor
C. Air lines connecting the parking brake to the trailer brakes
The emergency line also called the supply line has two purposes. First, it supplies air to the trailer air tanks. Second, the emergency line controls the emergency brakes on combination vehicles
17 / 25
A. immediately apply your tractor parking brakes.
B. begin to lower the trailer landing gear.
C. back up gently to ease pressure on the fifth wheel locking jaws.
Shut off trailer air supply to lock trailer brakes. Ease pressure on fifth wheel locking jaws by backing up gently, applying the parking brake while tractor is pushing against the kingpin.
18 / 25
A. fully loaded
B. empty
C. lightly loaded
The heavier the vehicle, the more work the brakes must do to stop it, and the more heat they absorb. But the brakes, tires, springs, and shock absorbers on heavy vehicles are designed to work best when the vehicle is fully loaded. Empty trucks require greater stopping distances because an empty vehicle has less traction.
19 / 25
A. service
B. parking
C. emergency
When the tractor protection valve closes, it stops any air from going out of the tractor. It also lets the air out of the trailer emergency line. This causes the trailer emergency brakes to come on
20 / 25
A. Trailer tank pressure to be lost
B. Tractor spring brakes to lock on
C. Trailer emergency / spring brakes to come on
You may not notice a major leak in the service line until you try to put the brakes on. Then, the air loss from the leak will lower the air tank pressure quickly. If it goes low enough, the trailer emergency brakes will come on.
21 / 25
A. None of the answers are correct
B. Usually need a glad hand converter
C. Often do not have spring brakes
D. Are easier to brake because they are heavier
Converter dollies and trailers built before 1975 are not required to have spring brakes.
22 / 25
A. Just enough to see light through it
B. At lease 1/2 inch
C. None
Make sure there is no space between upper and lower fifth wheel. If there is space, something is wrong, the kingpin may be on top of the closed fifth wheel jaws, and trailer would come loose very easily.
23 / 25
A. On the left side and on the front center
B. On the front left or rear left corner
C. On the right rear corner
Trailers will have yellow ABS malfunction lamps on the left side, either on the front or rear corner.
24 / 25
A. Curved line and signal line
B. Straight line and control line
C. Control line and signal line
The service line, also called the control line or signal line, carries air controlled by the foot brake or the trailer hand brake.
25 / 25
A. between 60 and 80 psi.
B. at normal pressure.
C. bled down to half the maximum pressure.
Make sure air pressure is up to normal before backing under the trailer.
1 / 25
Progress
0
Errors
