UniDrive Test

What is Automatic Traction Control (ATC)?

It allows the tires to grip the road better
It slows down the vehicle to a crawl
None of the above
It uses ABS sensors to monitor drive-wheel spin on slippery roads

Brake management systems are effective, when should drivers rely on them?

Only in poor weather
Never
At higher speeds
With heavy trailer loads

What does a steady ABS dash light indicate?

A problem with the ABS system
It's supposed to stay lit
A self-test is being performed
The vehicle has just been started

Antilock Brake Systems (ABS) are handled by sensors, modulators and a computer. Which statement is false? The modulators can be located...

Near the chambers they control
On the wheel itself
Wing mounted directly to the relay of the axle group
Wing mounted directly to the quick release valve of the axle group

If approaching a large amount of water on the road, what should you not do?

Reduce speed and cover the brake pedal when approaching
Test the brakes after exiting the water to help to dry them out
Maintain speed to keep momentum
Apply slight constant pressure to reduce the amount of water entering between the brake drums and shoes

What will a heavy load at the front of a trailer will cause the drive axles to have?

Better steering ability
More momentum to get up to speed
No difference compared to weight at the back of a trailer
Good traction for pulling and braking

What does water in the brake drums cause?

Reduction in braking ability
Nothing
It cools down the rotors
Acts as a lubricant

While braking on icy roads, what is not recommended?

Locking the wheels slightly to create friction and better traction
Light braking to allow for a slow control stop
Using snow tires to create better traction
Icing chains to create better traction

At what point do air brakes generate the most ongoing heat?

Travelling on downgrades
None of the above
Braking in rainy conditions
Braking from a high rate of speed

When were ABS brake mandatory on all air brake trucks, buses and trailers?

Since 1992
Since 2010
Since 2000
They're not mandatory

What is the biggest challenge for combination units causing the loss of brake balance?

Windy conditions
An uneven load distribution
Loss of air pressure
Low tire pressure

When should the driver check the ABS light on the trailer?

Never
After hearing the ABS activate
After start-up and occasionally when braking
While parked

When do auxiliary retarders work best?

At normal speeds
Whenever you want them to work
At lower vehicle speeds, and with the engine just under the rated rpm
At higher speeds

When using tire chains, what is not recommended?

In extreme conditions, it may be safer to park
Maintain normal speeds
Stop and check tightness after moving one vehicle length
Ensure they are correctly sized and tightly installed

When using runaway lanes, which does not apply?

Use the lane before the vehicle is out of control
Use the lane when the brakes no longer control the descent
You may use these lanes for other purposes
A narrow steep runaway lane will be very difficult to use if the vehicle is out of control

What potential problem can happen while applying brakes on combination vehicles?

Longer stopping distances
Skids or jackknifes
Nothing in particular
Wider turns

To descend safely in rural areas, which statement is false?

Follow advisory speed limits
Use 4-way flashers and stay in the right lane when possible
Use the vehicle's auxiliary retarder
Follow the actions of all the other drivers

What is the cause of almost all of the brake failures and runaway crashes?

No pre-trip inspections
Malfunction of a primary air cylinder
The brake system's inability to handle excessive heat
Poor maintenance

What is an Electric Driveline Retarder do?

It's an electromagnet that can pause the driveline
It's an electromagnet that can be placed beside an axle
It's an electromagnet that can in front of the transmission
It's an electromagnet designed to retard drive shaft rotation

What do ABS brakes do?

Allows for shorter stopping distances
None of the above
Prevents wheel lock-up and skids
Allows for a by-pass of the air brake system

To brake safely with ABS, what should you not do?

Pump the brakes
Apply firm, steady pressure to the brake pedal
Be cautious when steering around objects
Read the manufacturer's operational manual for instructions

If speed increases on a downgrade, what should you not do?

Continue down the hill using the auxiliary retarder to control the speed
Use a splitter valve
Repeat this process as necessary until the retarder can maintain the speed without service brakes
None of these

Trailers equipped with ABS brakes will have an ABS warning light. Where is this light located?

At the rear of the left side
At the rear of the right side
At the front of the right side
At the front of the left side

What are Hydraulic Driveline Retarders similar to?

Transmissions
Nothing
Torque converters
Clutch plate

With regard to ABS, which statement is false?

Make sure you know which units in a combination have ABS
ABS brakes are different with hydraulic brakes compared to air brakes
ABS brakes work with air brakes and hydraulic brakes
If the tractor or trailer do not have ABS, use a light, steady braking technique

The brakes under the empty rear of the trailer receiving the same amount of application air pressure as the drive axles, without the load to hold them down onto the ground, what can happen?

May cause the rear of the trailer to slide and swing
None of the above
Wheel lock-up
Longer braking distances

Whats another work for jackknife?

Yaw
Pull
Yank
Push

What do exhaust retarders essentially do?

To help the back pressure stays within the engine's back pressure capacity
To help block the flow of exhaust
To help the back pressure move
To help dissipate the exhaust

What does a flashing ABS dash light indicate?

A problem with the ABS system
Controlling the service brakes
None of the above
The vehicle has just been started

When descending on unfamiliar grades, which statement is false?

On extreme grades, change gears often
Stay in a low gear until the steepest part of the descent
There is a balance between the retarder, speed, load and grade is reached
Select a low gear and turn on the retarder before the hill is crested

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