Combination
To test the tractor protection valve, charge the system, turn off the engine, and
Step on and off the brake pedal several times
You should put the starter switch key into your pocket while you perform the pre-trip inspection because
Someone could start and move the truck
When you’re about to start down a steep downgrade, what should you do?
Shift to a low gear
When is it on to leave your truck unattended without applying the brake
never
Low-slung vehicles can be risky at railroad crossings because
They are more likely to get stuck on raised railroad crossings
How many reflective warning triangles must you carry with you for emergencies?
3
The minimum tread depth for all tires except the front tires is
2/32 inch
Slack adjuster free play needs to be adjusted if it moves more than _____ inches when you pull it?
1
After you lock the kingpin into the fifth wheel, how should you check the connection
Pull the tractor ahead gently with the trailer brakes locked
What is the definition of a hazard?
A road user or road condition that presents a possible danger
You should inspect wheel bearing seals for
leaks
The air loss for a straight truck or bus with the engine off and brakes on should not be more than
3 psi in one minute
Even before antilock braking systems (ABS) were required, some vehicles already had them. How do you check if your vehicle has ABS?
Look under the vehicle for the ECU and wheel speed sensor wires coming from the back of the brakes.
What might happen of you swing wide to the left before you turn right?
Someone might try to pas you on your right
An anti-lock braking system (ABS) will
Keep your wheels from locking when you break hard
excessive use of the service brakes results in overheating which can lead to
expansion of the brake drum
When you’re pulling doubles or triples, the shut off valves should always be
Open except for those on the last trailer.
Why should you use a helper when you are backing?
Because every truck has blind spots
If you feel drowsy while driving, what should you do?
Pull off the road and get some sleep
you must make an emergency stop, you should brake so you:
Can steer and you vehicle stays in a straight line
On a trailer, where is the yellow antilock brake(ABS) malfunction lamp located?
On the left front or left rear corner
Where should you place your warning devices of you must stop on a one-way road or divided highway?
10 ft., 100ft., & 200ft. toward approaching traffic
Always try to back toward the driver’s side because
You can see better, watching the vehicle’s rear from the side window
At what pressure does the low air pressure light come on
60psi
To prevent a rollover, cargo should be
Spread evenly across the rig and as low as possible
In what two situations should you downshift?
Starting down a hill and entering a curve
How many tiedowns are required for a 20-foot load?
2
The brake system that applies and releases the brakes when the driver uses the brake pedal is the ____ brake system
service
To drive a triple combination vehicle, you must have
A class A CDL with a doubles/triples (T) endorsement
How long does it take a typical tractor-trailer to clear a double railroad track?
More than 15 seconds
How many hours of sleep per night does the average adult need?
7-8 hours
A straight truck or bus air brake system should not leak at a rate greater than ___ psi per minute with the engine off and the brakes released
2
The tractor protection valve is designed to close automatically if the air pressure range specified by the manufacture, typically
20-45psi
What is the best way to check what is going on behind and to sides of you vehicle?
Check your mirrors regularly
The most important hand signal that you and a helper should agree on is
Stop
An air brake system is fully charged at what psi
125
Before you start to uncouple, you must
Make sure the ground is solid and can support the weight of the trailer
Total stopping distance equals
perception distance + reaction distance + braking distance
If the engine is not overheated, is it completely safe to remove the radiator cap?
No
The spring brakes on brake chambers on a straight truck will bring you to a stop when air pressure drops below ____ psi
20
During uncoupling, you should disconnect the electrical cable and
hang it up with the plug down
If you double your speed, how much distance will it take to brake to a stop?
Four times as much
How do you test a vehicles hydraulic brakes for leaks?
Pump the brakes 3 times, Then apply firm pressure for 5 seconds.
excessive heat caused by using your brakes too often can also cause
brakes to fade or fail
Semi-trailers made before 1975 that are equipped with air brakes
Often do not have spring brakes
If you are traveling at 55mph in a 30-foot vehicle, you should leave how many seconds of following distance?
4 sec.
What is the main reason to perform a vehicle inspection?
To make sure the vehicle is safe
the s-cam
forces the brake shoes against the inside of the brake drum
Under good driving conditions, you should leave at least one second of following distance behind the vehicle ahead of you for every ____ feet of your vehicle’s length
10
On which of the following types of fires should you NOT use a B/C fire extinguisher?
Wood
What are the main differences between aggressive driving and road rage?
Intent to do harm
If your vehicle has an alcohol evaporator, it is there to
reduce the risk of icing in air brake valves in cold weather.