Arkansas CDL: Tanker Vehicles Practice Test

Not quite. The answer is can affect the handling of your vehicle.

Liquid surge can greatly affect your vehicle's handling. 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. On curves, side-to-side surge can cause a rollover even when traction is good.

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 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.

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 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.

Not quite. The answer is there is an even distribution of weight.

Some liquid tanks are divided into several smaller tanks by bulkheads. When loading and unloading the smaller tanks, pay attention to weight distribution. Don’t put too much weight on the front or rear of the trailer.

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 partly engage the clutch before you take your right foot off the brake.

When you start your vehicle, avoid rolling backward or else you may hit someone behind you. Set the parking brake whenever necessary to keep from rolling back. Release the parking brake only when you have applied enough engine power to keep from rolling back. If you have a manual transmission vehicle, partly engage the clutch before you take your right foot off the brake. On a tractor-trailer equipped with a trailer brake hand valve, the hand valve can be applied to keep from rolling back. Some modern automated manual transmissions (AMT) have a Hill Start or Hill Assist feature. When the vehicle is in gear on an incline and the driver releases the service brakes, the AMT will prevent the vehicle from rolling back for about three seconds, giving you time to apply the accelerator.

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 Environment

The S.T.A.M.P.E.D. acronym is widely used to assist you in obtaining the correct hoses and fittings for your needs. S: the required size of the hose; T: the temperatures to which the hose will be subjected; A: the application (use) to which the hose will be put; M: the types of material (liquid, gas, etc.) that will have to flow through the hose; P: the maximum working pressure of the hose; E: the required fittings at the ends of the hose; D: the date at which the hose must be delivered to you.

Not quite. The answer is Spring brakes (or wheel chocks)

When parking a tank trailer, you should always apply the parking brake. On a modern trailer equipped with air brakes, applying the parking brake control will exhaust air from the brake chambers and cause the spring brakes to come on. However, an old trailer may lack spring brakes and instead use compressed air to set the parking brakes. In this case, you must chock the wheels to prevent the trailer from moving. A leak somewhere in the air braking system may cause the parking brakes to fail eventually.

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 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 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 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 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 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.

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 may require a longer stopping distance than full trucks.

With all types of combination vehicles, the weight of cargo helps the wheels get traction. When a combination vehicle is empty or lightly loaded, its braking distance increases. The very stiff suspension springs and strong brakes give poor traction and make it very easy to lock the wheels.

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.