Kansas CDL: Tanker Vehicles Practice Test

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 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 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 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 15 to 50

If your vehicle is placarded, you must stop between 15 and 50 feet from the nearest rail at a railroad crossing. After you have done so, proceed once you are sure that no train is approaching, and do not shift while you are on the tracks.

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 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 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 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 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 S-cam drum brake.

Foundation brakes are present on each wheel. In North America as of this writing, S-cam drum brakes are much more common than wedge or disc brakes.

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 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.

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 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 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 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 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 You should avoid backing whenever you can.

Backing up a large vehicle is always dangerous, even with a helper. Try to avoid backing up as much as possible.

Not quite. The answer is You should avoid traveling alongside other vehicles whenever possible.

Whenever another vehicle is traveling alongside yours, there's always a chance that the vehicle might try to move into your lane and accidentally hit your vehicle. Also, the vehicle is blocking you from changing lanes. It's safer to find an open spot where there are no vehicles on either side of you. (Of course, that may not be possible in heavy, congested traffic.)