Maine CDL: Tanker Vehicles Practice Test

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 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 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 Upshift.

If your hydraulic brakes fail while you're driving, try pumping the brake pedal to build up enough hydraulic pressure to stop your vehicle. If this fails, downshift to use engine braking and apply the parking brake. Release the parking brake before you lock the wheels. If all else fails, look for an escape route. Head for an escape ramp or an open field and let your vehicle slow to a stop.

Not quite. The answer is If the wheels are skidding, you cannot control the vehicle.

In an emergency, avoid hard braking. Hard braking can lock the wheels, which may cause a skid and loss of control. Instead, use stab braking (unless your vehicle has antilock brakes) or controlled braking.

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 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 surging.

When a tank is not completely filled, the liquid has room to move around. It can slosh back and forth or side to side. This is called surging.

Not quite. The answer is should avoid braking as you're turning.

The liquid cargo can surge both back and forth and side to side. This makes a skid more likely if you brake in a sharp turn. And it also makes it more likely that the skid will lead to a rollover.

Not quite. The answer is Keep a steady foot on the brake and don't release the brake too soon.

To control the effects of surge, brake far in advance of a stop. Maintain steady pressure on the brakes and don't release them too soon.

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 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 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 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 leaks.

When you inspect your tank vehicle, the most important thing to check for is leaking tanks. It is illegal to knowingly carry liquids or gases in a leaking tank. Check around and underneath the vehicle for any signs of leaks. Also check all tanks, hoses, pipes, and connections for leaks.

Not quite. The answer is driving too fast for conditions.

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 distribution of weight.

If the tank is divided into several smaller tanks (compartments) by bulkheads, pay attention to the distribution of weight whenever you load or unload these tanks. Avoid putting too much weight on the front or the back of your vehicle.

Not quite. The answer is allowance for expansion of liquid.

When liquid heats up, it expands, and outage is the space in the tank that is 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 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 both of the above are true.

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. Also, some liquids are so dense that a full load may exceed the legal weight limit. For these reasons, you may not be able to fill your tanks completely.