Tennessee CDL: Tanker Vehicles Practice Test

Not quite. The answer is bulkheads.

Separators that divide a space into liquid-tight compartments are called bulkheads. The tank on a tanker vehicle may have bulkheads to divide the tank into separate compartments.

Not quite. The answer is Much of the tanker's weight is high up off the ground.

An object with a high center of gravity is top-heavy; much of its weight is high off the ground. Top-heavy objects are more prone to toppling over. Loaded tankers tend to have a high center of gravity because the tanks are so tall. This makes liquid tankers more prone to rolling over. Tests have shown that tankers can roll over on curves even at the speeds posted. On curves, slow down well below the posted speeds.

Not quite. The answer is You should not load a cargo tank completely full.

Some liquids expand significantly when they warm up. To fill a tank with such a liquid, you must leave some room in the tank (called "outage") to take the expansion. Different liquids expand at different rates as the temperature increases. In science, the percentage increase of expansion for a given change in temperature is called the coefficient of thermal expansion. This value depends on the type of liquid. You need to find out how much outage you will need to allow for the type of liquid you'll be hauling.

Not quite. The answer is At the end of each working day

Oil and water can start to collect in the bottom of an air tank and can cause brake failure if it's not drained. Unless your vehicle automatically drains the air tanks, you should drain them at the end of each working day so the moisture and oil will not freeze or coagulate and cause your brakes to fail.

Not quite. The answer is Slow down gradually.

Braking on a slippery surface can lock the wheels and cause a skid. Brake gently and slow down very gradually.

Not quite. The answer is the movement of the liquid.

It takes special skills to drive a tanker carrying liquid cargo because of the vehicle's high center of gravity and the possibility that the liquid cargo may surge forward and backward or from side to side. The liquid surge can push the vehicle dangerously forward or sideways, which can cause a rollover. Once a side-to-side surge begins, unless the driver takes action, the tank will keep swaying more and more until the vehicle rolls over.

Not quite. The answer is the front or the rear

Bulkheads help separate the load. When loading such tanks, distribute the weight evenly. Avoid putting too much weight on the front or the rear of the vehicle.

Not quite. The answer is may exceed legal weight limits.

A full tank of dense liquid (such as some acids) may exceed legal weight limits. For this reason, you may not be able to completely fill the tank with a dense liquid.

Not quite. The answer is Get out of your vehicle and away from the tracks.

If your vehicle gets stuck on a railroad track, get everyone including yourself out of your vehicle. Have everyone walk at about a 45-degree angle to the tracks in the direction from which you expect a train to approach. That way, if your vehicle is hit, none of you will be struck by flying debris. Once you've reached a safe location, call 911 or the telephone number on the railroad crossing sign.

Not quite. The answer is a rollover.

A side-to-side surge exerts lateral (sideways) forces on the tank. Once a side-to-side surge begins, unless the driver takes action, the tank will keep swaying more and more until the vehicle rolls over.

Not quite. The answer is If it has to stay very clean

For transporting food products such as milk, regulations prohibit baffled tanks because of the difficulty of cleaning the inside of a baffled tank.

Not quite. The answer is your vehicle will stay in a straight line.

If you must brake in an emergency, brake in a way that keeps your vehicle in a straight line while still letting you turn if necessary. You can use the "controlled braking" method or (in a vehicle without antilock brakes) the "stab braking" method.

Not quite. The answer is liquids or gases.

According to federal regulations, you need a tank endorsement to drive a tank vehicle that requires you to have a CDL. A tank vehicle is defined as a commercial motor vehicle that transports a bulk cargo of liquid or gas within one or more tanks that are either permanently or temporarily attached to the vehicle. [49 CFR 383.5],

Source: 49 CFR 383.93

Not quite. The answer is four

You placard your vehicle to warn everyone around you that you are transporting hazardous materials. Therefore, you must have placards on all four sides of your vehicle.

Not quite. The answer is the top of the tank

In general, the Maximum Allowable Working Pressure (MAWP) of a pressurized tank is the maximum pressure that the weakest part of the tank can handle in normal operation. For a cargo tank on a motor vehicle, the federal definition of MAWP assumes that the weakest part is at the top of the tank.

Source: 49 CFR 178.320

Not quite. The answer is Read the vehicle's manual to learn how to do it.

Tank vehicles come in many models and sizes, each with special items that you need to check during an inspection. Read the vehicle's manual to learn how to inspect it properly.

Not quite. The answer is Your brakes may fail because of water freezing.

Your air tanks hold a mixture of water and compressor oil. If left inside to collect at the bottom, the water may freeze and cause brake failure.

Not quite. The answer is Within 500 feet behind the vehicle

If you park on the side of the road and the view of your vehicle is obscured by a hill or curve, place a reflective triangle far enough (up to 500 feet) behind your vehicle so it can be seen by other drivers.

Not quite. The answer is can have strong forward-and-backward surge.

Baffles are often used in tanks to reduce forward-and-backward surge. Nevertheless, certain cargoes, such as milk and other liquid food products, must be transported in smooth bore, unbaffled tanks. (Sanitation regulations forbid the use of baffles because they are hard to keep sufficiently clean.) These tanks are liable to have very strong forward-and-backward surge. Be very careful when driving vehicles with such tanks.

Not quite. The answer is side-to-side surge.

Some tanks have baffles: bulkheads with holes through which the liquid can flow forward or backward. These baffles significantly reduce forward-and-backward surge but not side-to-side surge, so the risk of surge causing a rollover remains.