Grade, Curves and Load Handling Flashcards

A tank vehicle is carrying a partially filled, smooth-bore (unbaffled) tank. What is the main hazard of the liquid in this tank during braking and acceleration?

Answer: The liquid surges forward and backward, which can push the vehicle

Liquid in a partly filled smooth-bore tank sloshes back and forth freely when you speed up or brake. That surge can push the vehicle in the direction the liquid is moving.

Why must a tank vehicle driver take a curve at a lower speed than a typical straight-body truck would?

Answer: The liquid's weight raises the center of gravity, which increases rollover risk

Liquid cargo sits high and raises the vehicle's center of gravity, so a tank vehicle can roll over at speeds that would be safe for other trucks. Slow down before the curve.

A tank vehicle driver is approaching a sharp curve on an exit ramp. What is the safest technique?

Answer: Slow to a safe speed before the curve, then drive through it smoothly

Reduce speed before the curve so you can steer through smoothly without needing to brake or accelerate abruptly. Heavy braking or acceleration in a curve can trigger rollover or loss of control.

Which statement about baffles in a tank is correct?

Answer: Baffles reduce front-to-back surge but do not stop side-to-side movement of the liquid

Baffled tanks have walls with holes that slow the liquid's front-to-back surge. Liquid can still move from side to side, which can cause rollover.

A tank is carrying a very heavy (dense) liquid. Why is the tank often filled only partway?

Answer: To prevent exceeding legal weight limits

Some liquids are so dense that a completely full tank would exceed legal weight limits. The tank is filled only partly to stay legal.

Compared with a fully loaded, completely filled tank, why can a half-filled tank be harder to control when you brake?

Answer: The liquid has room to move, and its surge pushes the vehicle as you brake

A partly filled tank gives the liquid room to move, so braking sends a wave of liquid forward that pushes the vehicle. A full tank has little room for surge.

A tank vehicle driver is going down a long, steep downgrade with a partially loaded tank. Which action is best?

Answer: Select a low gear before descending and use engine braking with controlled, light brake use

Choose a low gear before starting down the grade so the engine helps hold your speed, and use the brakes lightly as needed. This avoids brake fade and sudden speed changes that cause surge.

A driver of a tank vehicle on a slippery road must stop at an intersection ahead. Which approach reduces the risk caused by liquid surge?

Answer: Brake early and gently, and leave extra room to stop

Braking early and gently reduces the strength of the surge and gives more room to stop. Hard braking sends a large wave of liquid forward, which can push the vehicle into the intersection.

Why is it still important to drive carefully when a tank vehicle is empty?

Answer: Residue and vapors can remain in the tank and may still be dangerous

An empty tank that carried hazardous liquids or flammable materials can still contain residue and vapors. It must be handled as if it were loaded.

A tank vehicle has several separate compartments divided by bulkheads. What is the main effect of the bulkheads on liquid movement?

Answer: They stop liquid from moving between compartments, which limits surge within each compartment

Bulkheads divide the tank into separate compartments, so liquid cannot flow between them. Each compartment holds a smaller volume, which limits how much surge can build.