- Unbolt the air compressor from the engine as visually inspecting it while attached is nearly impossible
- Check the condition and tightness of the belt (if belt driven)
- Take the front cover off so you can look inside the vacuum seal
- Visually check oil level inside the air compressor using a dip-stick
Quote From Page 66 Of The CDL Manual:
Check air compressor drive belt if compressor is belt driven. If the air compressor is belt driven, check the condition and tightness of the belt. The belt should be in good condition.
TruckingTruth's Advice:
Some air compressors are gear driven, in which case, no belt will be present. Otherwise, be sure to check the belt to be sure it isn't frayed, cracked, off its tracks, or otherwise broken.
- Any speed of 20 mph or more above the posted speed limit
- Any speed of 15 mph or more above the posted speed limit
- Any speed of 10 mph or more above the posted speed limit
- Any speed of 25 mph or more above the posted speed limit
Quote From Page 8 Of The CDL Manual:
Excessive speeding involving any single offense for any speed of 15 mph or more above the posted speed limit.
The following may also result in excessive speeding:
- Failure to reduce speed to avoid an accident.
- Driving too fast for conditions.
- Exceeding the speed limit in a school zone.
TruckingTruth's Advice:
Excessive speeding is considered a "serious traffic violation." Two serious traffic violations within a three-year period results in a two-month disqualification. Three serious traffic violations in the same period results in a four-month disqualification.
- All time loading and unloading your truck
- All time inspecting or servicing your truck, including fueling
- All driving time
- All of these are considered on duty time
Quote From Page 0 Of The CDL Manual:
What Is Considered On Duty Time?
The 60 / 70 hour limit is based on how many hours you work over a 7 or 8 day period. Just what kind of work is considered on duty time? It includes all time you are working or are required to be ready to work, for any employer. Here are some specific activities which are considered to be on duty time:
- All time spent at a plant, shipping / receiving facility, terminal, or other facility of a motor carrier, unless you are in your sleeper berth or have been relieved of all work related responsibilities.
- All time inspecting or servicing your truck, including fueling it and washing it.
- All driving time.
- All other time in a truck unless you are resting in a sleeper berth.
- All time loading, unloading, supervising, or attending your truck; or handling paperwork for shipments.
- All time spent providing a breath, saliva, hair, or urine sample for drug / alcohol testing, including travel to and from the collection site.
- All time spent doing any other work for a motor carrier, including giving or receiving training and driving a company car.
- All time spent doing paid work for anyone who is not a motor carrier, such as a part-time job at a local restaurant.
The bottom line is that on duty time includes all time you are working for a motor carrier, whether paid or not, and all time you are doing paid work for anyone else.
- Between 50 and 75 psi
- Between 10 and 20 psi
- Between 20 and 45 psi
- Between 100 and 120 psi
Quote From Page 68 Of The CDL Manual:
The spring brakes will come on when the air pressure drops into the 20 to 45 psi range
- Used to hold all liquid or gas to one side of the tank
- A divider inside a tank to section off liquid or gas
- A device that is placed on the top of liquid or gas and compresses it as low as possible to decrease the center of gravity
- Used to elevate liquid to a higher center of gravity
Quote From Page 84 Of The CDL Manual:
Some liquid tanks are divided into several smaller tanks by bulkheads. When loading and unloading the smaller tanks, the driver must pay attention to weight distribution. Do not put too much weight on the front or rear of the vehicle.
How many violations have occurred on the below log?

- 3
- 2
- 1
- 0
Quote From Page 0 Of The CDL Manual:

Violations: There is a 14 hour rule violation from 5:00 p.m. - 10:00 p.m.
Explanation - 11 Hour Limit: After 10 consecutive hours off duty, the driver had 11 hours of driving time available at 2:00 a.m. The driver completed 11 total hours of driving by 10:00 p.m. and went off duty, so there were no violations of the 11 hour rule.
Explanation - 30 Minute Break: Once the driver began driving at 2:00 a.m., a 30 minute break was not needed until 10:00 a.m. (8 hours after first going on duty). Since the driver went off duty at 8:00 a.m. and spent more than 30 minutes off duty (sleeper berth), the driver was never in violation. During the hours of 5:00 p.m. to 10:00 p.m., the driver was only on duty (driving) for 5 hours before moving back to off duty. Even though the 14 hour limit was being violated during that time, the 30 minute break provision was not violated.
Explanation - 14 Hour Limit: After 10 consecutive hours off duty, the driver had 14 hours available beginning at 2:00 a.m. The driver reached the 14 hour limit at 4:00 p.m. and violated the rules by driving an additional 5 hours without first obtaining either: 10 consecutive hours off duty; or 8 consecutive hours in a sleeper berth. To remain in compliance the driver should have either:
- Obtained one additional hour off duty or in the sleeper berth in the middle of the day (for a total of 10 consecutive hours off duty) or;
- Remained in the sleeper berth for 8 consecutive hours, rather than only 7. Had the driver remained in the sleeper for 8 consecutive hours, that 8-hour sleeper period would have been excluded from the 14 hour calculation and the driver would have remained in compliance.
- Sliding the tractor 5th wheel
- Sliding the trailer tandems
- Moving the cargo toward the rear of the trailer
- Adding more fuel to the tanks
Quote From Page 0 Of The CDL Manual:
The final key point to understand when it comes to weight transfer is that none of the methods of redistributing weight between the different sets of axles, including sliding your 5th wheel, sliding your tandems, or moving the cargo around will have any affect on your gross weight.
The only way to affect the gross vehicle weight would be to add or remove weight from the vehicle. Adding or burning off fuel, or adding or removing cargo would be two examples of ways to alter the gross vehicle weight.
- The position of the trailer's tandems
- The position of the tractor's 5th wheel
- Moving the cargo toward the front or rear of the trailer
- None of these affect the gross vehicle weight at all
Quote From Page 0 Of The CDL Manual:
TruckingTruth's Advice:
- The overall length of the cargo after being loaded into the trailer.
- The center point of the cargo's weight.
- The average height of the cargo above the trailer floor.
- The distance from the front of the trailer to the center point of the cargo.
Quote From Page 0 Of The CDL Manual:
TruckingTruth's Advice:
- The tractor's drive axles and the steer axle
- The tractor's drive axles and the trailer tandems.
- It only removes weight from the trailer tandems
- The steer axle and the trailer tandems