West Virginia CDL: Tanker Vehicles Practice Test

Not quite. The answer is the type of liquid.

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 the likely percentage increase for the type of liquid you'll be hauling, and allow enough room (called outage) for the expansion to take place.

Not quite. The answer is 70%

It takes special skills to operate a tank vehicle safely. About 70% of tank truck drivers haul hazardous materials, such as gasoline. Doing so takes even more special skills. Such drivers must obtain both a tank vehicle (N) endorsement and a hazardous materials (H) endorsement on their CDLs, or a combination tank vehicle and hazardous materials (X) endorsement.

Not quite. The answer is 20 feet long.

An ISO standard portable tank is a metal tank enclosed in a steel frame. The frame is 19.8556 feet (6.05 meters) long, 7.874 feet (2.40 meters) wide, and either 7.874 feet (2.40 meters) high or 8.374 feet (2.55 meters) high.

Not quite. The answer is MC-331

MC-331 cargo tanks carry gases that are liquefied under relatively high pressure (maximum allowable pressure of 100–500 psi). The cargo tank has a circular cross section and rounded ends. These tanks are commonly used to carry such gases as propane and liquefied petroleum gas (LPG).

Not quite. The answer is with holes that let liquid flow through.

Tank baffles are bulkheads with holes through which the liquid can flow, but with less force than in tanks without such baffles. These baffles significantly reduce forward-and-backward surge but not side-to-side surge, so the risk of surge causing a rollover remains.

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 on slippery roads.

When you're coming to a stop, the liquid in the tanks tends to surge forward. If you're on a slippery surface, the surge may shove your truck forward into another vehicle or an intersection. Learn how your tanker handles in such situations.

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 MC-306 (DOT-406)

MC-306 (DOT-406) cargo tanks carry liquids under very low or no pressure (maximum allowable pressure of 3 psi for MC-306 and 4 psi for DOT-406). The cargo tank has an oval or elliptical cross section and is usually compartmented. These tanks are commonly used to carry gasoline, diesel fuel or fuel oil, and other flammable liquids.

Not quite. The answer is Unstable loads such as hanging meat or livestock can require extra caution on curves.

Hanging meat can sway on curves, and livestock can move around. These motions can affect the handling of your vehicle. One reason that you must drive a tanker vehicle carefully is that liquid surge can push the vehicle in the same direction as the surge. This can be especially hazardous on icy roads, where your truck may be pushed forward a dangerous amount, maybe past a red light into an intersection. Another concern is that liquid expands when it warms. Outage is the space in the tank that must be allocated to handle the expansion. Different types of liquids expand by different amounts. Therefore, the amount of outage you will need depends on the type of liquid.

Not quite. The answer is speed up slightly

The posted speed for a curve may be safe for cars but not for tankers because of their relatively high center of gravity. Tests have shown that a tanker can roll over on a curve when traveling at the posted speed. The safest way to take a curve in a tanker is to slow down before the curve and then accelerate slightly through the curve.

Not quite. The answer is both a hazardous materials (H) endorsement and a tank vehicle (N) endorsement.

A tank vehicle (N) endorsement qualifies you to haul liquids or gases. However, if those liquids or gases are classified as hazardous materials, you must also have a hazardous materials (H) endorsement to haul them. To obtain each of these endorsements, you must pass a specialized knowledge test. Note: These days, if you obtain both endorsements, your CDL may include the combined endorsement code X (tank vehicle and HazMat) instead of both H and N.

Not quite. The answer is use controlled or stab braking.

Sudden or hard braking can cause the liquid in the tank to surge forward, pushing your vehicle forward. If you must stop quickly, use controlled or stab braking instead. (However, don't use stab braking if your vehicle is equipped with antilock brakes.)

Not quite. The answer is driving too fast.

Over-braking and over-steering can cause skids. Both over-braking and over-steering are more likely when you're driving too fast for the current road conditions.

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 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 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 an unbaffled tank.

A smooth bore tank is another name for an unbaffled tank. Without baffles, there is likely to be strong 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.

Not quite. The answer is You should not apply the brakes while turning.

To avoid a crash or other hazard, keep both hands on the steering wheel so you can turn as quickly as possible. However, turn just enough to avoid the hazard. A too-sharp turn risks a skid or rollover. While turning quickly, avoid braking. Braking in a turn can easily lock the wheels and cause a skid.

Not quite. The answer is stop braking, turn quickly, and countersteer.

To recover from a drive-wheel braking skid, first stop braking. The rear wheels will unlock and roll again so there will be no more tendency to slide sideways. Then quickly steer your vehicle back on course. You may find that your vehicle will overshoot and keep on turning, possibly skidding in the opposite direction. Countersteer to counteract this. Note: This maneuver takes some practice. You should become proficient in it before you actually need to use it.