Bobtail tractors are tractors that are not attached to any semitrailers. When operating a bobtail, you should be aware that stopping can be difficult and that it will take a longer distance to come to a complete stop than a tractor attached to a loaded semitrailer.

Aggressive driving is defined as operating a motor vehicle in a selfish, bold, or pushy manner. Road rage is defined as operating a motor vehicle with the intent of doing harm to others, or the intent of physically assaulting another driver or their vehicle.

You should always slow to a safe speed before entering a curve. Slowing while within the curve could cause a skid.

Watch the gauges in your vehicle before starting a trip. After starting your vehicle's engine, the coolant temperature should begin a gradual rise to the normal operating range.

For safe operation, a commercial motor vehicle needs a tread depth of 4/32 of an inch in every major groove on the front tires, and a tread depth of 2/32 of an inch on other tires.

When making a left turn, you should wait until you reach the center of the intersection before actually beginning to turn. Due to off-tracking, the left side of your vehicle could hit another driver if you begin turning too early.

Always change lanes slowly and smoothly. If you did not see drivers who are already using the lane you wish to occupy, this will give them a chance to get out of your way or honk their horns to alert you. Always signal when changing lanes.

When parking on a level surface, you should use wheel chocks. If the vehicle is not equipped with spring brakes, this is essential to prevent the trailer from moving.

When driving, you should continually scan the road for possible hazards. Form plans about what you will do if the hazards develop into emergencies.

Vehicles equipped with Anti-Lock Braking Systems (ABS) have yellow malfunction lights to indicate issues in the braking system.

In situations where a driver cannot use a parking brake, wheel chocks can be used to hold a parked vehicle in place on a level surface.

There are two air brake systems in a dual air brake system. The systems share a set of brake controls, but each system has its own tanks, hoses, and lines.

Federal and state laws require drivers to inspect their vehicles before every trip, regardless of length.

Most newer heavy-duty vehicles use dual air brake systems. A dual air brake system has two separate air brake systems which use a single set of brake controls.

B:C fire extinguishers are designed to work on electrical fires and burning liquids. Don't pour water on an electrical fire.

During a trip, you should regularly make checks to ensure that your vehicle is operating properly. Check the instrument panel and gauges; look at your mirrors; and examine the tires, cargo, and lights. Use all of your senses and be alert for anything that could be an early indication of trouble.

If you need to back your trailer but cannot back up in a straight path, you should back on a curved path toward the driver's side of the vehicle. This will allow you the best possible visibility while backing.

Brakes out of adjustment will fade before those that are properly adjusted. Brake adjustment must be checked frequently to help prevent brake issues.

Vehicles with trailers are vulnerable to rollover due to the "crack-the-whip" effect, which is caused by rearward amplification. Rearward amplification varies from vehicle to vehicle, so it is important that drivers are aware of the rearward amplification of their specific vehicles.

When inspecting the convertor dolly, make sure all components are present and in proper working condition. Be sure to check the upper and lower fifth wheel, the air lines, and the electric lines. The fifth wheel should be properly greased and securely mounted.