Missouri CDL: Tanker Vehicles Practice Test

Not quite. The answer is your vehicle may jackknife.

If your drive wheels are skidding, it's likely because you applied the brakes too hard and locked the drive wheels. A drive-wheel skid can let the trailer push the tractor sideways, causing a sudden jackknife. To recover from this type of skid, the first thing to do is stop braking. The drive wheels will unlock and start to roll again.

Not quite. The answer is Watch gauges and mirrors and use your senses to check for problems.

During your trip, you should be watching a number of things, such as your mirrors, gauges, instruments, lights, tires, and cargo. Use several of your senses – sight, hearing, smell, and feel – to detect possible trouble.

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 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 Rear

Shut-off valves are used in the service and supply air lines at the rear of trailers used to tow other trailers. These valves permit closing off the air lines when another trailer is not being towed. You must check that all shut-off valves are in the open position except the ones at the rear of the last trailer, which must be closed.

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 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 individual tanks over 119 gallons or a total of at least 1,000 gallons.

You must have a tank vehicle (N) endorsement to drive a vehicle with one or more individual tanks over 119 gallons or multiple tanks totaling at least 1,000 gallons.

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 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 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 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 There will be less front-to-back surge than there is in a tanker without baffles.

Baffled tanks have bulkheads with holes to reduce forward-and-backward surge. This will reduce the chance that forward surge will push your vehicle dangerously forward when you're slowing or stopping. However, these bulkheads don't significantly reduce side-to-side surge, so rollovers can still occur.

Not quite. The answer is Before loading it, driving it, or unloading it

You should inspect a tank vehicle before loading it, driving it, or unloading it. This is to ensure that it is safe to carry out these activities and the vehicle can safely hold its liquid or gas contents.

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 250 feet.

You should always be able to stop within the distance you can see ahead. Fog, rain, or other conditions may require that you slow down to be able to stop in the distance you can see. If your headlights let you see only 250 feet ahead, adjust your speed so that you can stop within that distance. Otherwise, by the time you notice a hazard ahead, you may not be able to stop in time to avoid it.

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 Inspect the vehicle.

Before loading, unloading, or driving a tanker, you must inspect the vehicle. This makes sure that the vehicle is safe to carry liquids or gases and is safe to drive. Tank vehicles have special items that you need to check. Study the vehicle's operator manual to learn how to inspect your tank vehicle.

Not quite. The answer is the distance you can see ahead.

No matter what type of motor vehicle you are driving at night (even a passenger car), you must drive at a speed that lets you stop within the range of your headlights. (In the dark, you have no way of knowing what lies beyond the reach of your headlights.) With low beams, you can see ahead only about 250 feet. Yet if you're driving a vehicle with air brakes at 45 mph, your vehicle's stopping distance may be as long as 346 feet. Hence, with low beams at 45 mph, you will not be able to brake in time to avoid a hazard that you see.

Not quite. The answer is baffles.

Baffles are devices that regulate the flow of liquid. In a tank vehicle, baffles are a type of bulkhead with holes through which liquid may flow but with reduced force.