Review Questions - Click On The Picture To Begin...
- You would not apply the brakes until your speed reaches 40 mph
- At 40 mph you apply the brakes hard enough to gradually reduce your speed to 35 mph
- All of these answers are correct
- Release the brakes once you reach 35 mph
Quote From The CDL Manual:
Proper Braking Technique - The use of brakes on a long and/or steep downgrade is only a supplement to the braking effect of the engine. Once the vehicle is in the proper low gear, the following is a proper braking technique:
1. Apply the brakes just hard enough to feel a definite slowdown.
2. When your speed has been reduced to approximately 5 mph below your "safe" speed, release the brakes. (This brake application should last for about 3 seconds.)
3. When your speed has increased to your "safe" speed, repeat steps 1 and 2.
TruckingTruth's Advice:
This braking technique is used in the real-world. While on a decline, you should set a specific "safe speed" such as 40mph. As your speed increases, you should depress the brake pedal and quickly (but safely) slow down to 35mph (5mph below your safe speed). Once you reach 35mph, release the brakes until you reach 45mph (5mph above your safe speed) and repeat the process. By releasing the brakes, you give your brakes time to cool, avoiding brake fade.
- All of these are reasons to select a lower gear before starting down a hill
- You may not be able to shift into a lower gear once speed has already built up
- 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
- You will lose all engine braking effect while shifting gears
Quote From 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.
- Overheating brakes
- Brakes which are out of adjustment
- Excessive braking on a downgrade
- Moisture on the brake pads
Quote From The CDL Manual:
Brake Fading or Failure - Brakes are designed so brake shoes or pads rub against the brake drum or disks to slow the vehicle. Braking creates heat. But brakes are designed to take a lot of heat. However, brakes can fade or fail from excessive heat caused by using them too much and not relying on the engine braking effect.
Brake fade also is affected by adjustment. To safely control a vehicle, each brake must do its share of the work. Brakes out of adjustment will stop doing their shares before those that are in adjustment. The other brakes can then overheat and fade, and there will not be enough braking available to control the vehicle.
Brakes can get out of adjustment quickly, especially when they are used a lot; brake linings also wear faster when they are hot. Therefore, brake adjustment must be checked frequently.
- As brakes cool down, you have to apply them harder and harder to get the same stopping power
- When brakes on one side of the vehicle wear faster than brakes on the other side of the vehicle
- The natural wear and tear on brake pads
- When brakes heat up, you have to apply them harder and harder to get the same stopping power
Quote From The CDL Manual:
If the brakes become too hot, they may start to "fade." This means you have to apply them harder and harder to get the same stopping power. If you continue to use the brakes hard, they can keep fading until you cannot slow down or stop at all.
- At low RPMs with the transmission in a high gear
- At high RPMs with the transmission in a high gear
- At low RPMs with the transmission in a low gear
- At high RPMs with the transmission in a low gear
Quote From The CDL Manual:
You must use the braking effect of the engine as the principal way of controlling your speed. The braking effect of the engine is greatest when it is near the governed RPMs and the transmission is in the lower gears. Save your brakes so you will be able to slow or stop as required by road traffic conditions.
- All commercial vehicles are required to stop at all railroad crossings
- Stopping before a railroad crossing is never allowed
- Commercial vehicles only need to stop at railroad crossings without gates
- The nature of the cargo makes a stop mandatory under state or federal law
Quote From The CDL Manual:
A complete stop is required at a grade crossing when:
- The nature of the cargo makes a stop mandatory under state or federal regulations.
- Such a stop is otherwise required by law.
- Use the same gear or lower 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
- Use the same gear or higher gears than what was needed for the uphill grade
Quote From 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.