- Two separate air brake systems that use a single set of brake controls
- A system which does not have spring brakes and instead, uses a second S-Cam system for its emergency brakes
- A single air brake system that uses two sets of brake controls
- A fail safe system where when one air brake system fails below 60 psi, the second system will keep the emergency brakes from activating
Quote From Page 65 Of The CDL Manual:
Most newer heavy-duty vehicles use dual air brake systems for safety. A dual air brake system has two separate air brake systems that use a single set of brake controls. Each system has its own air tanks, hoses, lines, etc. One system typically operates the regular brakes on the rear axle or axles. The other system operates the regular brakes on the front axle and possibly one rear axle. Both systems supply air to the trailer if there is one. The first system is called the "primary" system. The other is called the "secondary" system.
- All of these should be taken into consideration when loading liquid into a tank
- The weight of the liquid
- Legal weight limits
- The amount the liquid will expand in transit (outage)
Quote From Page 85 Of The CDL Manual:
A full tank of dense liquid (such as some acids) may exceed legal weight limits. For that reason, you often may only partially fill tanks with heavy liquids. The amount of liquid to load into a tank depends on:
- The amount the liquid will expand in transit.
- The weight of the liquid.
- Legal weight limits.
- Total weight of a single vehicle plus its load.
- Total weight of a powered unit plus trailer(s) plus the cargo.
- Weight transmitted to the ground by one axle or one set of axles.
- Maximum GCW specified by the manufacturer for a specific combination of vehicles plus its load.
Quote From Page 52 Of The CDL Manual:
You are responsible for not being overloaded. Following are definitions of weights:
- Gross vehicle weight (GVW): Total weight of a single vehicle plus its load.
- Gross combination weight (GCW): Total weight of a powered unit plus trailer(s) plus the cargo.
- Gross combination weight rating (GCWR): Maximum GCW specified by the manufacturer for a specific combination of vehicles plus its load.
- Axle weight: Weight transmitted to the ground by one axle or one set of axles.
- Tire load: Maximum safe weight a tire can carry at a specified pressure. This rating is stated on the side of each tire.
- Suspension systems: Suspension systems have a manufacturer's weight capacity rating.
- Coupling device capacity: Coupling devices are rated for the maximum weight they can pull and/or carry.
- The yellow and red air control knobs located in the cab of a truck
- Used in the service and supply air lines at the back of trailers used to tow other trailers
- Designed to turn off the truck engine when a brake failure occurs
- Placed at each trailer spring brake and are designed to engage the emergency brakes when air pressure becomes too high
Quote From Page 74 Of The CDL Manual:
Shut-off valves (also called "cut-out cocks") are used in the service and supply air lines at the back of trailers used to tow other trailers. These valves permit closing the air lines off when another trailer is not being towed. You must check that all shut-off valves are in the open position except the ones at the back of the last trailer, which must be closed.
TruckingTruth's Advice:
Only trailers designed to be pulled with another trailer behind it will have a shut off valve. If you are only pulling one trailer, make certain the valve is fully in the closed position or it will leak air out of the air system.
- Tiedown
- Edge Protector
- Working Load Limit
- Void Filler
Quote From Page 1 Of The CDL Manual:
Tiedown:
A combination of securing devices which form an assembly that attaches cargo to, or restrains cargo on, a vehicle or trailer, and is attached to anchor point(s).
- Prevent damage to the cargo
- Avoid fines and citations
- Prevent loss of load
- Make it look pretty
Quote From Page 1 Of The CDL Manual:
Why?
- Loss of life
- Loss of load
- Damage to the cargo
- Damage to the vehicle
- Issuance of citations/fines to driver/carrier
- The vehicle being placed Out-of-Service.
- A crash
- Use the same gear or lower gears than what was needed for the uphill grade
- Use the same gear or higher gears than what was needed for the uphill grade
- Drivers should wait until they are about 1/4 of the way down the hill before deciding which gear to use
- Downhill grades should always use 5th gear or lower
Quote From Page 39 Of The CDL Manual:
Be in Right Gear Before Starting Down Grade - Shift the transmission to a low gear before starting down the grade. Do not try to downshift after your speed has already built up. You will not be able to shift into a lower gear. You may not even be able to get back into any gear and all engine braking effect will be lost. Forcing an automatic transmission into a lower gear at high speed could damage the transmission and also lead to loss of all engine braking effect.
A good rule for older trucks is to use the same gear going down a hill that you would need to climb the hill. However, newer trucks have low-friction parts and streamlined shapes for fuel economy. They also may have more powerful engines. This means they can go up hills in higher gears and have less friction and air drag to hold them back going down hills. For that reason, drivers of modern trucks may have to use lower gears going down a hill than would be required to go up the hill. Know what is right for your vehicle.
- One hand on the steering wheel and one hand on the gear shift
- One hand on the steering wheel and one hand on or near the air horn
- One hand on the steering wheel and one hand on the emergency brake
- Keep both hands on the steering wheel
Quote From Page 128 Of The CDL Manual:
When driving through an intersection:
- Check traffic thoroughly in all directions.
- Decelerate and yield to any pedestrians and traffic in the intersection.
- Do not change lanes or shift gears while proceeding through the Intersection.
- Keep your hands on the wheel.
TruckingTruth's Advice:
The examiners actively check to see your hand placement. Whenever possible, keep both hands on the wheel. This is especially true while driving through an intersection.
- 9
- 7
- 5
- 4
Quote From Page 4 Of The CDL Manual:
There are seven special CDL endorsements and one restriction that require testing. In addition, drivers who do not pass the air brake portion of the exams are restricted to driving vehicles without air brakes.
The endorsements are:
- 1. Charter Bus (C)
- 2. Combination Tank and Hazardous Materials (X)
- 3. Double/Triple Trailers (T)
- 4. Passenger Vehicles (P)
- 5. School Bus Endorsement (S)
- 6. Tank Vehicles (N)
- 7. Vehicles Carrying Hazardous Materials (H)
Restrictions:
1. Vehicle Without Air Brakes (L-Restriction)
TruckingTruth's Advice:
We highly recommend that everyone get all endorsements available because:
- You don't want to restrict your opportunities
- The tests are fairly quick, simple, and inexpensive
- You're already going through the process of learning the materials anyhow
So make sure you get all of the endorsements.
- 60 degrees
- Between 60 and 90 degrees
- Less than 45 degrees
- 180 degrees
Quote From Page 5 Of The CDL Manual:
- Attach at least one tiedown against front of row of coils to restrain against forward motion. If possible, angle between tiedown and deck should be less than 45, when viewed from the side of the vehicle.
- Attach at least one tiedown against rear of row of coils to restrain against rearward motion. If possible, angle between tiedown and deck should be less than 45, when viewed from the side of the vehicle.
- Attach at least one tiedown over top of each coil or side-by-side row of coils to restrain against vertical motion. Tiedowns going over top of coil(s) must be as close as possible to eye of coil.
- Arrange tiedowns, blocking, or bracing to prevent shifting or tipping in all directions.