Maryland CDL: Tanker Vehicles Practice Test

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 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 Surge can move the truck in the direction the liquid waves move.

One of the reasons 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 a truck may be pushed forward a dangerous amount, maybe past a red light into an intersection.

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 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 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 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 starting or stopping.

Smooth bore tanks lack baffles or bulkheads to reduce forward-and-backward surge. When you start from a stopped position, the liquid will surge backward, pushing your vehicle backward. When you try to stop, the liquid will surge forward, pushing your vehicle farther forward. Perform such actions slowly and carefully.

Not quite. The answer is Side-to-side

Baffled tanks have bulkheads with holes through which the liquid can flow. The bulkheads 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 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 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 be within 25 feet of the tank.

The person in charge of loading and unloading a cargo tank must be sure a qualified person is always watching. This person watching the loading or unloading must be alert, have a clear view of the cargo tank, be within 25 feet of the tank, know of the hazards of the materials involved, know the procedures to follow in an emergency, be authorized to move the cargo tank and able to do so.

Not quite. The answer is There will be less front-to-back surge than in a tank without baffles.

A baffled tank has bulkheads with holes through which the liquid can flow forward or backward but with less force than if there were no baffles. This will reduce forward-and-backward surge, making it less likely that surge will push your vehicle forward when you try to stop.

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 Wet roads can double the stopping distance at any speed.

To control surge, know the stopping distance of your vehicle and brake far in advance of a stop whenever possible. Bear in mind that your vehicle's stopping distance on wet roads will be about double its stopping distance on dry roads.

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 4 psi.

One of the most common types of cargo tanks is the DOT-406, typically used for fuel delivery. A semi-truck with a DOT-406 mounted to the semitrailer is commonly called a "gasoline truck." DOT-406 tanks have a low maximum allowable working pressure (MAWP) of 4 psi.

Not quite. The answer is closed

Federal regulations require you to keep liquid discharge valves on a compressed gas tank closed except when you're loading or unloading the tank. Also, unless your engine runs a pump for product transfer, you must turn the engine off when you're loading or unloading.

Source: 49 CFR § 177.840

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

Baffled tanks have bulkheads with holes through which the liquid can flow but with less force than in a tank without such bulkheads.

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.