ABS system or (Anti-lock braking system): ABS is a safety anti-skid braking system. It can be found on most modern vehicles with a braking system. 

Active railroad crossing: This type of crossing has a traffic control device installed at the crossing to regulate traffic at the crossing.

Air brakes: Also called a compressed air brake system. They work by using compressed air which is stored in air storage tanks. The air pressure is used to apply the service brakes and release the parking brakes which activates only when wheels are about to lock up and to help you keep your vehicle under control while hard braking. 

Axle weight: The weight transmitted to the ground by one axle or one set of axles. 

BAC(Blood Alcohol Concentration): the percentage of alcohol that is in a person's blood. 

Braking Distance: the distance your vehicle will travel once you engage the brakes.

Brake fade: This is when the brakes have overheated to the point that they are no longer generating enough friction and do not have enough power to work properly.

CDL(Commercial Driver’s License): is a valid driver’s license that is required to drive large and heavy vehicles or vehicles with hazardous materials in the United States. There are three types of CDL that determine the kind of vehicle you're permitted to drive. The classifications are Class A, Class B, and Class C.

CMV(Commercial Motor Vehicle): any vehicle that transports cargo or passengers for an income. A few examples of this type of vehicle include semi-trucks, buses. 

Combination vehicle: When a tractor unit is attached to one or more trailers at a time.

Coupling: connecting and disconnecting—the tractor and the trailer. 

Double-clutching: using the clutch pedal twice during a single shift between gears. 

DOT(Department of Transportation): it is a federally run government agency that is responsible for planning and coordinating federal transportation projects. It also sets safety regulations for all major types of transportation.

Downshifting: shifting the transmission down from a higher gear to a lower gear. 

Endorsement: It is an authorization that shows that the CDL driver is permitted to drive specialized vehicles. An example of this would be a hazmat endorsement that would enable the driver to haul hazardous cargo.  

En route: When a driver is on their way to the next destination. 

Escape ramp(runaway truck ramp): This ramp is used for emergency use if a truck is having braking problems and is unable to stop. This stretch of an area next to a roadway generally is located near the middle or the end of a long and steep downgrade of the highway. 

Floating gears: is the process of shifting without using the clutch. You do this by carefully accelerating and simply drifting the shifter into gear when the RPMs reach the right level of revolutions per minute. 

Front header board(headache racks): this rack is designed to guard the driver by protecting them in case of an emergency stop. For example, If the driver has to stop quickly, their cargo will not hit the tractor, keeping the driver safe. 

Gear splitter(mono shift): The gear splitter uses a high-low division while shifting. Instead of having a high and low section, the gears are split into two so that each position of the gear shift is used for two gears (one high and one low).

GCWR: The value specified by the manufacturer of the power unit, if the value is displayed on the Federal Motor Vehicle Safety Standard (FMVSS) certification label; or the sum of the gross vehicle weight ratings (GVWR) or the gross vehicle weights (GVW) of the power unit and the towed unit(s), or any combination thereof, that produces the highest value. 

Implied Consent: This is a Federal law that says the CDL holder has to consent to take an alcohol or drug test if he or she is suspected of driving under the influence, such testing can be done by the state and law enforcement. If a CMV driver refuses to submit to or fails a test, the driver will face enforceable consequences by the state.

Hazmat(Hazardous Material): substances such as flammable or poisonous material that may pose a reasonable risk to health, property, or the environment.

Highway-railroad grade crossing: this is an intersection where a roadway crosses railroad tracks at the same level or grade. Such crossings can be either public and private roads.

Jackknife: When a truck and its trailer go into a skid the trailer swings out and stops to form a 90-degree angle between the trailer and the cab of the truck. 

Jake brake or Engine retarder: uses the engine to slow down and control the vehicle.

Move-over laws: These laws require drivers to slow down and change lanes when approaching a roadside incident or emergency vehicle. Signs are posted on roadways in states that have such laws. 

Out-of-service: TheNorth American Standard (OOSC) can put a vehicle Out-of-Service if it inspects and finds violations that prohibit a motor carrier or driver from operating a commercial motor vehicle. This could be for a specified period of time or until the condition of the vehicle is corrected. 

Some of the reasons for placing a vehicle or its driver out-of-service might have to do with holding multiple licenses for multiple states, transportation of placarded vehicles without proper paperwork or proper license, violations of out-of-service restrictions and many more.

Passive railroad crossing: This type of crossing does not have any type of traffic control device at the crossing.  

Perception distance: This is the distance your vehicle travels from the time your eyes see a hazard until your brain recognizes it.

Placarded vehicle: Placards are signs put on the outside of a vehicle that identify the hazard class of the cargo. These placards need to be displayed on all four sides of a transport vehicle. 

Range selector(neutral safety switch): An electrical switch that tells your vehicle what gear your transmission is in when you turn on your vehicle.  

Reaction distance: The distance you will continue to travel before you physically hit the brakes, in response to a hazard you have seen.

RPM(Revolutions per minute): this is the measurement of how fast an engine is operating. 

Stopping distance: the following distance that a person who is driving needs in order to bring a vehicle safely to a complete stop.

Tandem axle trailer: has two sets of axles–one right behind the other. The extra tires allow the trailer to handle extra weight. This also allows the trailer to be more stable at higher speeds. It makes the vehicle easier to handle on highway conditions.

Tank vehicle: this is a motor vehicle designed to carry liquids or gases on roads. Some examples include—a tank truck, gas truck, fuel truck. 

Tire load: The maximum safe weight a tire can carry at a specified pressure. This rating is stated on the side of each tire.

Trailer slew or trailer swing: When a trailer skids to one side. This can occur especially when the trailer is empty or lightly loaded, or if there are violent gusts of a crosswind.

Upshifting: shifting the transmission up from a lower gear. The driver should shift gears up when the tachometer is around 3,000 RPMs. 

Weigh station: This is a checkpoint along a highway to inspect commercial vehicle's weight. 

Winterfront: This is a cover that protects your truck's grille. It reduces and redirects the wintry cold air from flowing into your truck's grille while still allowing enough air to flow to all areas of the cooling system.