Ohio CDL Tanker Test key terms

A commercial motor vehicle built to carry liquids or gases in a permanently mounted tank with a capacity of 119 gallons or more per tank, or a portable tank of 1,000 gallons or more.

The enclosed container permanently attached to a tank vehicle that holds the liquid or gas being transported, including its shell, heads, baffles, and attached piping.

A bulk container that is not permanently attached to the vehicle, is loaded and unloaded as a unit, and is secured to the chassis for transport.

The main cylindrical or rectangular body of the cargo tank that contains the product and carries the internal pressure or weight of the lading.

An internal wall inside a cargo tank that divides the tank into separate compartments, adds structural strength, and limits how far liquid can shift during driving.

A perforated or partial internal partition that slows the front-to-back movement of liquid in a tank without fully dividing it into separate compartments.

The forward and backward movement of liquid inside a partly filled tank as the vehicle speeds up, slows down, or changes direction, creating shifting forces on the vehicle.

The momentum-driven force produced when liquid in a tank sloshes against the tank ends, which can push the vehicle forward or backward and make braking and steering harder.

The empty space left above the liquid surface in a tank, which allows the product to expand with temperature changes and provides room for movement.

The unfilled portion of a tank, measured as the distance from the liquid surface to the top of the tank, used to confirm the tank is not overfilled.

A cargo tank with no internal baffles or bulkheads, so liquid can move freely from end to end and produce the strongest surge forces.

A cargo tank fitted with internal partitions that reduce the distance liquid can travel, lowering surge forces and improving vehicle control.

The point where the weight of the vehicle and its load is concentrated; in a tank vehicle it is higher and can shift as liquid moves, raising rollover risk.

A condition where the vehicle's weight sits well above the axles, making the vehicle more likely to tip over in turns, on ramps, or during sudden maneuvers.

A crash in which the vehicle tips onto its side or roof, often caused by taking a curve too fast, especially with a partly filled tank and a high center of gravity.

The movement of product inside a tank from one side or end to another, which changes weight distribution and can destabilize the vehicle during turns and stops.

How the combined weight of the vehicle and cargo is spread across the axles, which affects steering, braking, and stability and must stay within axle limits.

The maximum weight a single axle or axle group may carry under law and manufacturer ratings; overloading reduces braking and handling performance.

Loading a vehicle beyond its gross vehicle weight rating or axle limits, which increases stopping distance and raises the risk of tire and brake failure.

The maximum total weight a vehicle is designed to carry, including the vehicle, fuel, driver, passengers, and cargo, set by the manufacturer.

The required practice of bringing the vehicle to a complete stop, setting the parking brake, and shutting off the engine before loading or unloading a tank.

Wedges placed against the tires to prevent the vehicle from rolling during loading or unloading, used in addition to the parking brake.

The mechanical brake that holds a stopped vehicle in place; it must be set and checked before any loading, unloading, or tank inspection activity.

Filling a tank beyond its safe capacity so that too little outage remains, which can cause product to escape through vents or overflow when it warms up.

A system that captures fuel vapors displaced from a tank during loading instead of releasing them to the air, reducing fire and health hazards.

The controlled release of air or vapor from a tank through vents or hatches to prevent pressure buildup or vacuum as product is loaded or unloaded.

A device on a cargo tank that opens automatically to release excess internal pressure or vacuum, protecting the tank from rupture or collapse.

A valve that quickly stops the flow of product from a tank in an emergency, often required at loading and unloading points and remotely operable.

The fixed structure where a tank vehicle is loaded, typically equipped with loading arms, grounding connections, and safety controls for product transfer.

Connecting the vehicle and transfer equipment to earth to drain static electricity before and during loading or unloading of flammable liquids.

Electrically connecting two pieces of equipment, such as the tank and the loading arm, so they are at the same potential and cannot spark between them.

An electric charge that builds up as liquids flow or splash during transfer and can ignite flammable vapors if it discharges as a spark.

A liquid that gives off vapors capable of igniting at normal working temperatures, requiring special handling, placarding, and vapor controls.

A diamond-shaped sign placed on the vehicle that identifies the hazard class of the cargo being carried, warning others in an emergency.

The document that describes the hazardous cargo being transported, including proper shipping name, hazard class, and quantity, kept accessible to the driver.

Guidance carried with hazardous cargo that tells responders and the driver how to handle spills, fires, and exposures involving the specific material.

A check of the tank, hoses, valves, and fittings for drips, cracks, or loose connections performed before driving and at stops during the trip.

The pipes and fittings attached to a cargo tank that carry product during loading and unloading and must be checked for leaks and damage.

A strap, chain, or fitting that secures a portable tank or container to the vehicle so it cannot shift or fall off during transport.

The use of tiedowns, locks, and restraints to keep cargo from moving; portable tanks and containers must be secured to meet federal requirements.