Podcast
Questions and Answers
What is a modulating valve?
What is a modulating valve?
Control handle on the dashboard that may be used to apply spring brakes gradually.
What can be used to release the spring brake in some vehicles?
What can be used to release the spring brake in some vehicles?
A separate air tank.
You need at least ______ tread in the front tires and ______ tread in other tires.
You need at least ______ tread in the front tires and ______ tread in other tires.
4/32 inch; 2/32 inch
What steering wheel play degree can make it hard to steer?
What steering wheel play degree can make it hard to steer?
If more than one-fourth of the leaf springs are leaking, what will happen?
If more than one-fourth of the leaf springs are leaking, what will happen?
What warning devices are required for parked vehicles?
What warning devices are required for parked vehicles?
How much should pressure build from 50 psi to in 3 minutes?
How much should pressure build from 50 psi to in 3 minutes?
What is considered safety equipment in a vehicle?
What is considered safety equipment in a vehicle?
Oil pressure should be between ______ psi and ______ psi.
Oil pressure should be between ______ psi and ______ psi.
How do you test for hydraulic leaks?
How do you test for hydraulic leaks?
When must drivers inspect trucks and cargo?
When must drivers inspect trucks and cargo?
What is road speed measured in?
What is road speed measured in?
What is engine speed measured in?
What is engine speed measured in?
What do retarders help with?
What do retarders help with?
What are the four basic types of retarders?
What are the four basic types of retarders?
When should drivers turn off the retarder?
When should drivers turn off the retarder?
How far ahead should you look when driving?
How far ahead should you look when driving?
When should mirror adjustment take place?
When should mirror adjustment take place?
What are curved mirrors called?
What are curved mirrors called?
What should you do when turning?
What should you do when turning?
If you stop on any road, when must you put out your warning devices?
If you stop on any road, when must you put out your warning devices?
On a two-way street, warning placement should be at ______ feet ahead and ______ feet back.
On a two-way street, warning placement should be at ______ feet ahead and ______ feet back.
For a one-way street, warning placement should be ______, ______, and ______ feet back.
For a one-way street, warning placement should be ______, ______, and ______ feet back.
What is perception distance?
What is perception distance?
What is reaction distance?
What is reaction distance?
What is braking distance?
What is braking distance?
What is total stopping distance at 55 mph?
What is total stopping distance at 55 mph?
What happens when you double your speed from 20 to 40 mph?
What happens when you double your speed from 20 to 40 mph?
What occurs when you triple your speed from 20 to 60 mph?
What occurs when you triple your speed from 20 to 60 mph?
When you increase speed to 80 mph, what is the impact on braking distance?
When you increase speed to 80 mph, what is the impact on braking distance?
How should you adjust speed on slippery surfaces?
How should you adjust speed on slippery surfaces?
Hydroplaning can occur at speeds as low as what?
Hydroplaning can occur at speeds as low as what?
When is the braking effect greatest?
When is the braking effect greatest?
What is the number one cause of injury and death in roadway work zones?
What is the number one cause of injury and death in roadway work zones?
How many seconds do you need for each 10 feet of vehicle?
How many seconds do you need for each 10 feet of vehicle?
What are two dangers in traveling next to others?
What are two dangers in traveling next to others?
How should you avoid blinding others?
How should you avoid blinding others?
When should you inspect tires in hot weather?
When should you inspect tires in hot weather?
What is a passing crossing?
What is a passing crossing?
What is an active crossing?
What is an active crossing?
How long does it take a typical tractor trailer to cross a track?
How long does it take a typical tractor trailer to cross a track?
What must you use as the principal way of controlling your speed?
What must you use as the principal way of controlling your speed?
What should you do when going down grade?
What should you do when going down grade?
What is not always the safest thing to do in an emergency?
What is not always the safest thing to do in an emergency?
What is a key action to avoid while turning?
What is a key action to avoid while turning?
When avoiding a crash, when should you avoid using your brakes?
When avoiding a crash, when should you avoid using your brakes?
What are the common reasons for hydraulic brake failure?
What are the common reasons for hydraulic brake failure?
What does the anti-lock braking system (ABS) do?
What does the anti-lock braking system (ABS) do?
What are ways a skid can be caused?
What are ways a skid can be caused?
When a front wheel skids, how can you stop the skid?
When a front wheel skids, how can you stop the skid?
What are the basic steps to take at an accident scene?
What are the basic steps to take at an accident scene?
How should you distribute cargo in a vehicle?
How should you distribute cargo in a vehicle?
What must the load limit of the securing article be?
What must the load limit of the securing article be?
What can too little weight on the driving axles cause?
What can too little weight on the driving axles cause?
Cargo should have at least how many tie downs?
Cargo should have at least how many tie downs?
What is the cut-out and cut-in pressure for the governor of the air suppresses?
What is the cut-out and cut-in pressure for the governor of the air suppresses?
What is set to open if the pressure in the air tanks exceeds 150?
What is set to open if the pressure in the air tanks exceeds 150?
What is the most common type of foundation brake?
What is the most common type of foundation brake?
When does the low pressure alarm come on?
When does the low pressure alarm come on?
On large buses, at what pressure does the low pressure alarm typically go off?
On large buses, at what pressure does the low pressure alarm typically go off?
What pumps air into the storage tanks/reservoirs?
What pumps air into the storage tanks/reservoirs?
What can compressed air contain that is bad for the air brake system?
What can compressed air contain that is bad for the air brake system?
What happens if more than one-fourth of the spring leaf is broken?
What happens if more than one-fourth of the spring leaf is broken?
When will tractor and straight truck spring brakes come on fully?
When will tractor and straight truck spring brakes come on fully?
What do some vehicles such as buses have a separate air tank for?
What do some vehicles such as buses have a separate air tank for?
What does a dual air brake system utilize?
What does a dual air brake system utilize?
What should you allow time for before driving a vehicle with a dual air system?
What should you allow time for before driving a vehicle with a dual air system?
If a slack adjuster moves more than about one inch at the push rod attachment, what does it probably need?
If a slack adjuster moves more than about one inch at the push rod attachment, what does it probably need?
How long should the pressure build from 85-100 psi in dual air systems?
How long should the pressure build from 85-100 psi in dual air systems?
What should you do with a fully charged air system typically at 125 psi?
What should you do with a fully charged air system typically at 125 psi?
What two things help you prevent rollover?
What two things help you prevent rollover?
Large combination vehicles take longer to stop when they are?
Large combination vehicles take longer to stop when they are?
What is the earliest and best way to recognize that the trailer has started to skid?
What is the earliest and best way to recognize that the trailer has started to skid?
When a vehicle goes around a corner, what happens to the rear wheels?
When a vehicle goes around a corner, what happens to the rear wheels?
If you cannot complete your turn without entering another traffic lane, what should you do?
If you cannot complete your turn without entering another traffic lane, what should you do?
When trying to back up with a trailer, what is best?
When trying to back up with a trailer, what is best?
Why should you never use the hand valve for parking?
Why should you never use the hand valve for parking?
What does the tractor protection valve do?
What does the tractor protection valve do?
When does the tractor protection valve close automatically?
When does the tractor protection valve close automatically?
What are the two air lines every combination vehicle has?
What are the two air lines every combination vehicle has?
What are coupling devices used to connect the service and emergency air lines from the truck or tractor to the trailer?
What are coupling devices used to connect the service and emergency air lines from the truck or tractor to the trailer?
Flashcards are hidden until you start studying
Study Notes
Modulating Valves and Brake Systems
- Modulating valve controls spring brakes via dashboard handle for gradual application.
- Air tank in some vehicles is used to release spring brakes.
- Minimum tread for front tires is 4/32 inch, and 2/32 inch for rear tires.
- A steering wheel play of 10 degrees (two inches) can hinder steering capabilities.
- If over 25% of leaf springs are leaking, the vehicle must be taken out of service.
Safety and Inspection Requirements
- Required warning devices for parked vehicles include three reflective triangles, six fuses, or three liquid burning flares.
- Air pressure should rise from 50 psi to 90 psi in three minutes, governed cutout activates at 120-140 psi.
- Safety equipment must consist of spare fuses, reflective triangles, or burning flares.
- Oil pressure range for vehicles should be 5-20 psi; operating range is 35-75 psi.
Inspection and Reaction Distances
- Inspect cargo securement within 50 miles of trip start and every 150 miles or three hours thereafter.
- Reaction distance averages at 3/4-1 second, typically covering 61 feet at 55 mph; braking distance at this speed may require about 216 feet.
- Total stopping distance at 55 mph is approximately 419 feet, and tripling speed increases braking distance exponentially.
Driving Conditions and Safety Measures
- On slippery roads, reduce speed by one-third (from 55 mph to 35 mph); on icy roads, cut speed by half.
- Hydroplaning can occur at speeds as low as 30 mph during heavy rainfall.
- Braking effects are optimal when near governed RPMs with the transmission in lower gears.
Handling Emergencies and Vehicle Dynamics
- In case of an accident, protect the scene, notify authorities, and attend to the injured.
- Distribute cargo low to maintain stability; heavier items should be placed at lower sections.
- Maintain proper tie-downs: two for every section up to ten feet.
Air Brake System Mechanics
- A dual air brake system operates off a single set of controls and requires compressor pressure of at least 100 psi before driving.
- Low pressure alarms activate below 60 psi; large buses may trigger at 80-85 psi.
- The tractor protection valve helps retain air pressure within the truck's brake system during trailer separation.
Skidding and Steering Techniques
- Front wheel skids can be controlled by allowing the vehicle to decelerate; avoid braking abruptly.
- Trailer hand valves shouldn't be used for parking, as this may lead to air pressure loss and unlock brakes.
- When turning, ensure to avoid using brakes while in motion and to turn wide if needed to avoid crossing lanes.
Coupling and Trailer Safety
- Glad hands are the devices that connect service and emergency air lines between truck and trailer.
- Always keep cargo low and take turns slowly to prevent rollovers; this is crucial for stability with combination vehicles.
- The rear wheels of a vehicle take a different path than the front, causing off-tracking during turns.
By familiarizing yourself with these key points, driving and safety practices can be effectively understood and applied.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
