Because liquids expand when their temperatures increase, some space must be left in a tank to accommodate the expansion. This space is referred to as "outage." The amount of required outage is different for different liquids.

Mirror adjustment should be checked prior to the start of any trip. If your vehicle has a trailer, the trailer must be straight in order for the mirrors to be checked accurately.

It is important that the driver of a CMV always downshifts before entering a curve.

If your trailer begins to drift while you are backing, you should correct the drift immediately by turning the top of the steering wheel in the direction of the drift.

Check hydraulic brakes by pumping the brake pedal three times before applying firm pressure to the pedal for five seconds. The pedal should not move. If it does, there may be a leak or some other problem in the braking system.

Reduce your speed when traveling on surfaces that provide reduced traction. Reduce your speed by one-half or more when traveling on packed snow.

Wheels or rims that have had welding repairs are not safe for use. They should be replaced before the vehicle is taken on the road.

To avoid hitting anything behind you, make sure that your vehicle does not roll back when you start from a complete stop.

Driving a tank vehicle filled with liquid cargo is challenging because tanks have high centers of gravity and because liquid cargo is vulnerable to surge. The movement of liquid cargo in transit can make a vehicle unstable.

Stay aware of upcoming obstacles and hazards by consistently watching the road at least 12 to 15 seconds ahead of your vehicle. When traveling at highway speeds, this is equivalent to about a quarter of a mile.

Never use the trailer hand valve while operating your vehicle. Using the trailer hand valve while driving can cause your trailer to skid.

In some vehicles, it may be necessary to leave the engine running when checking the automatic transmission fluid level.

A faulty exhaust system is a serious safety hazard. It may allow poisonous fumes to enter the vehicle's cab or sleeper berth.

Tractor protection controls in older vehicles may be operated by levers instead of knobs. If an air supply control is set in its "emergency" position, the air supply will be stopped and the trailer emergency brakes will be applied.

Before driving a tank, make sure the vents and manhole covers have gaskets and that they close correctly. Vents should be kept clear to ensure that they work correctly.

If your hydraulic braking system will not build up the pressure needed to slow or stop your vehicle, there are a few possible solutions. Try shifting into a lower gear, pumping the brakes, and/or using the emergency brake.

The suspension system performs the vital functions of holding up the vehicle and its load while keeping the axles in place. Defects in the suspension are therefore extremely dangerous.

When inspecting your vehicle's engine, check the belts for tightness and excessive wear. The amount of "give" that is safe for each belt in a given engine will vary, so learn what is appropriate for your vehicle.

After a vehicle is started, the warning lights and buzzers should go out after a few seconds. If the warning signals do not turn off, there may be something wrong with the vehicle.

It is essential that you are aware of what is happening on all sides of your vehicle at all times. Scan the road ahead and make regular checks of the mirrors on both sides of your vehicle while you are driving.