27 - CDL Flashcards
What will help you find problems that could cause a crash or breakdown?
Vehicle inspection
What tire tread depth is needed for the front and rear tires?
Front 4/32 Rear 2/32
The steering wheel play cannot be more than what?
10 degrees
At what pressure does the air tank governor kick on to cut-out the buildup of air?
120-140 PSI
What is the normal operating oil pressure?
35-75 PSI
What helps slow a vehicle and reduces the need for using your brakes?
Retarder
When driving at lower speeds how far is 12-15 seconds looking ahead? How far is it at higher speeds?
1 block at lower speeds
A quarter mile at highway speeds
When driving on the open highway how far is 12-15 seconds looking ahead?
0.25 miles
All of the following are good rules for using your turn signal except what?
Signal when ready to move
If you must stop on or by a one-way or divided highway, place warning devices how many feet away from the vehicle?
10 ft, 100 ft, 200 ft
Total stopping distance of a vehicle includes what?
Perception Distance + Reaction Distance + Braking Distance = Total Stopping Distance
The average perception time for an alert driver is what?
1.75 seconds
The average driver has a reaction time of what?
0.75-1.00 seconds
In ideal driving conditions and traveling 55 mph your vehicle will travel a minimun of how many feet for total stopping distance?
419 feet
In ideal conditions at 55 mph on dry pavement with good brakes it can take about how many feet of braking to stop the vehicle?
216 feet
If you double your speed from 20 to 40 mph how many times greater is the impact?
4 times
When the tires lose their contact with the road and have little or no traction it is called what?
Hydroplaning
What is not a type of distraction?
Weather distraction
Research shows that the odds of being involved in a safety-critical event like a crash or near-crash is how many times greater for drivers who engage in dialing a mobile telephone?
6 times
What is aggressive driving in the act of operating a motor vehicle in a selfish, bold, or pushy manner is called what?
Aggressive driving
Which brake system applies and releases the brakes when you use the brake pedal during normal driving?
Service
The governor controls when the air compressor will pump air into the air storage tanks. At around what psi will the air compressor governor “cut-out”, or stop pumping air into the system?
125
A safety relief valve is installed in the first tank the air compressor pumps air to. The safety valve protects the tank and the rest of the system from too much pressure. At what psi is the valve usually set to open?
150
Compressed air usually has some water and some compressor oil in it, which is bad for the air brake system, and tends to collect in the bottom of the air tanks. For example, the water can freeze in cold weather and cause brake failure. Unless the system has automatic drain valves, how often should air tank systems be drained?
Daily
On newer vehicles with air brakes, what mechanism do you use to put on the parking brakes?
Diamond-shaped, yellow, push-pull control knob
When does the Antilock Braking Systems (ABS) activate?
ABS only activates when wheels are about to lock up
During a walk-around inspection when checking the slack adjusters on S-cam Brakes, an adjustment is needed if a slack adjuster moves more than how many inch(es) where the push rod attaches to it?
1
Whilst fully applying the foot brake for one minute when testing the air leakage rate, if the air pressure drops more than how many pounds in one minute (single vehicle) or how many pounds in one minute (combination vehicle), is the air loss rate too much?
3, 4
When the engine is at operating rpms, within how many seconds should the pressure build from 85 to 100 psi?
45
In air brakes systems, what is referred to as the time required for the brakes to work after the brake pedal is pushed?
Brake lag
Air pressure should build from 50 to 90 psi within how many minutes?
3
When testing hydraulic breaks for a leak, you should pump the brake pedal how many times before applying firm pressure and holding for how many seconds?
3, 5
The distance your vehicle will travel, in ideal conditions, while you are braking is called?
Braking distance
The distance you will continue to travel, in ideal conditions, before you physically hit the brakes is referred to as?
Reaction distance
The distance your vehicle travels, in ideal conditions, from the time your eyes see a hazard until your brain recognizes it is called?
Perception distance
Hydroplaning can occur at speeds as low as?
30
A low air pressure warning signal is required on vehicles with air brakes. A warning signal you can see must come on before the air pressure in the tanks drops below what psi?
60
Tractor and straight truck spring brakes will come fully on when air pressure drops to a range between how much psi?
20-45
When testing the air leakage rate with a fully charged system(125 psi), turn off the engine, release the parking brake, and time the pressure drop. In one minute what should the loss rate be less than (psi) for single vehicles and combination vehicles?
2, 3
Total stopping distance for vehicles with air brake systems is made up of which sequence of factors?
Perception, reaction, brake lag, and braking
In a braking system what is the S cam used for?
to apply the brakes
The brake systems that applies and releases the brakes when the driver uses the brake pedal is?
service brake system
Anti-lock braking system does which of the following?
activates when your wheels are about to lock up
The air compressor will stop putting air into the tanks at what PSI?
125
Excessive heat caused by overuse of the service brakes can cause what?
brake fade
During normal driving brakes are held back by?
air pressure
What is the minimum tread depth for rear tires?
2/32’’
The air compressor governor controls?
when the air is pumped into the air tanks
What is the minimum tread depth for front steer tires?
4/32’’
The driver must be able to see a warning that is given before air pressure in the service air tanks falls below?
60 psi
The most common type of foundation brakes found on heavy vehicles is the?
‘S’’ cam
In the event of a brake system failure, the emergency brake system uses what to stop the vehicle?
parts of the service brakes and parking brake
Repeatedly pressing and releasing (fanning) the brake pedal may result in?
a loss in brake air pressure
You should know that your brakes are fading when?
you must push harder on the brake pedal to control your speed downhill
If their were to be an emergency air loss in the braking system at what PSI would the parking brake activate?
30-40 psi
You must have a CDL to drive a vehicle over what weight?
26,001 lbs.
Steering wheel play more than degree needs to be addressed or taken out of service?
10 degrees
How many leaf springs need to be missing to remove the vehicle form service?
4-Jan
Most good drivers are constantly looking how far ahead?
12-15 seconds
Which of the following is not part of the total stopping distance?
brake pedal distance
How many kinds of CDL endorsements are there?
6
The Passengers (P) endorsement is for drivers who wish to drive a vehicle having a design capacity to carry how many people?
16
How many miles per hour over the posted speed limit is considered “excessive speeding?”
15
What is the most important reason you inspect your vehilce?
Safety
If you do not wear your seatbelt, you are how many times more likely to be fatally injured if you are thrown from the vehicle?
4
Rust around the wheel nuts may be an indicator of what?
Loose nuts
Air pressure should build from 50-90 psi within how many minutes?
3
What is the formula for stopping distance?
Perception Distance + Reaction Distance + Braking Distance
What is more likely to cause hydroplaning?
Low tire pressure
At speed below 40 mph, how much space should you keep in front of you?
One second for each 10’ of vehicle
What is the general air tank “cut-out” level?
Around 125 psi
What is the general air tank “cut-in” level?
Around 100 psi
When determining the air leakage rate, what should the loss rate be on single vehicles?
2 psi for one minute
When the engine is at operating RPMS, the pressure should build from 85 psi to 100 psi within what amount of time?
45 seconds
What is the time required for the brakes to work after the brake pedal is pushed?
Brake lag
Regarding rims during the vehicle inspection, what can they NOT have?
Welding repairs
What is the definition of “aggressive driving?”
The act of operating a motor vehicle in a selfish, bold, or pushy manner, without regard for the rights or safety of others
How low of a speed can hydroplaning occur?
30 MPH
What must you use as the prinicpal way of controlling your speed on downgrades?
Braking effect of the engine
Regarding air brakes, when pushing down the brake pedal, what is the name of the valve you are pushing?
Treadle valve
What the number 1 reason to inspect your vehicle?
Safety
What can you do during your drive to help with safety of your vehicle?
watch gauges
What does rust around your wheel nuts mean?
they are loose
How much play in the steering wheel (in degrees)?
10
How many leaf spring missing will mean out of service?
one-fourth
How many steps in an inspection, according to CDL manual?
7
What helps you slow a vehicle down and reduces the need for using your brakes?
retarders
How far ahead should you look in the city?
1 block
How far ahead should you look on an open road?
quarter-mile
What are 3 good rules for turn signals?
Signal early,signal continuously and cancel your signal
What distance do you place warning devices on a one-way or divided highway?
10ft,100ft,200ft
What distance do you place warning devices on a curve or hill?
10ft , 100-500ft
What is total stopping distance?
Perception + reaction + braking
What is the avg, preception time of an alert driver?
1 3/4 seconds
what is the avg reaction time of an alert driver?
3/4-1 second
How far will your vehicle travel minimally at 55mph?
419ft
What is it called when tires have little or no traction on wet pavement?
Hydroplanning
How low of speed can you hydroplanning occur?
30 mph
How much space do you need at 40 mph?
1 second for each foot of your vehicle length
which lane to turn left if there is 2 left turning lanes?
right lane
What is the minimum tread depth in every major groove on the front tires?
4/32-inch
What is the minimum tread depth in every major groove on all tires besides the front tires?
2/32-inch
How many missing leaf springs will put a vehicle out of service, according to the VA CDL Manual?
One Fourth
Air pressure should build from 50 to 90 psi within how many minutes?
3 Minutes
The average driver has a reaction time of how many seconds?
3/4-1 Second
Which of the following does not contribute to total stopping distance?
Processing Distance
A low air pressure warning signal is required on vehicles with air brakes, this alarm must come on when the tanks fall below how many psi?
60 psi
Spring brakes come fully on when the air pressure drops to a range of what?
20-45 psi
Before driving away, the driver must allow the air compressor to build up a minimum of how many psi?
100 psi
At the end of every day, the drive should do what to ensure there is no water or oil in the air tanks?
Drain them with a quarter turn valve or by pulling a cable
When checking the brakes, a driver should park on level ground, chock the wheels, release the parking brake, and pull hard on each slack adjuster. If it moves more than how many inches, it probably needs to be adjusted?
1”
When checking brake drums, cracks longer than what will require replacement?
Half the width of the friction area
In order to check the air compressor cut-in and cut-out, once the air pressure meets its manufacturer’s specifications what is the next step?
Step on and off the brake to reduce the air tank pressure
When testing the air leakage rate, after turning off the engine and releasing the parking brake, what is an acceptable loss rate?
Less than two psi in one minute
When testing the air leakage rate, after releasing the parking brake and applying the foot brake for one minute, what is an acceptable air pressure drop?
Less than three psi in one minute
When the engine is at operating rpms, it should build air pressure from 85-100 in how many seconds?
45 seconds
When checking the spring brakes, the driver should continue to fan off the air pressure until the tanks fall below the manufactuer’s specification until what happens?
The spring brakes come on
What is the time required for the brakes to work after the brake pedal is pushed called?
Brake Lag
What happens as a result of excessive heat causing chemical changes in the brake lining, which reduce friction?
Brake Fade
Why should parking brakes be used with caution when the weather is wet and freezing?
The brakes could freeze
What is the gross vehicle weight rating that requires to have a cdl to operate?
26,001 pounds or more
All of the following are types of retarders except:
Air
When the temperature is close to how many degrees the bridges will freeze?
32°
How much space should you keep in front of you if you are driving a 40 foot vehicle?
4 seconds
What is the distance a vehicle needs to be for a driver be able to use the high beams?
500 feet
What is the minimum air pressure neede for a primary and secondary air brake system before driving?
100psi
What are the maximum leakage rates?
More than 3psi/ per min. for single vehicle or 4 psi/per min. for a combination vehicle
Apply your brakes all the way,release brakes when wheels lock up and apply brakes fully again when wheels start rolling. What is this method called?
Stab braking
What is the term used for the time required for the brakes to work after the brake pedal is pushed?
Brake lag
All of the following are things you can do to reduce the chance of a crash when tailgated except:
Make quick changes
Engaging in a conversation with a passenger is an example of what type of distraction?
Mental distraction
When is it ok to safely open the cap and add coolant even when engine is at operating temperature?
If the container is not part of the pressurized system
How must every railroad-highway crossing be aproached?
With expectation that a train is coming
What are the two types of railroad crossings?
Passive and Active
When the road crosses over more than one track, what does the sign below the cross-buck indicate?
Number of tracks
What do double tracks require?
A double check
When inspecting the engine compartment belts, what is the minimum play he belt should have?
1/2 inch
What is the minimum tread depth on tires?
4/32 front and 2/32 back
When backing, what is the most important hand signal you and the helper should agree on?
STOP
How far ahead should a driver look?
At least 12 to 15 secs.
What is the equation used to determine stopping distance?
perception distance+ reaction distance+braking distanc+brake lag distance=total stopping distance
The average perception distance time for an alert driver is 13/4 seconds. A vehicle traveling 55mph that accounts for:
142 feet
At 55 mph, the average reaction distance for an alert driver in ideal conditions is:
61 feet
Braking distance is defined by the VDOT CDL manual as:
the distance the vehicle will travel while braking in ideal conditions
