Virginia CDL: Tanker Vehicles Practice Test

Not quite. The answer is stop braking, turn quickly, and countersteer.

To recover from a drive-wheel braking skid, first stop braking. The rear wheels will unlock and roll again so there will be no more tendency to slide sideways. Then quickly steer your vehicle back on course. You may find that your vehicle will overshoot and keep on turning, possibly skidding in the opposite direction. Countersteer to counteract this. Note: This maneuver takes some practice. You should become proficient in it before you actually need to use it.

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 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 a high center of gravity.

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. Much of a loaded tanker's weight is carried five or six feet above the ground. This makes a tanker top-heavy, which makes it more prone to rollovers than other types of vehicles. Tests have shown that a tank vehicle can roll over at the speed limits posted for curves. The safest way to take a curve in a tanker is to slow down well below the posted speed limit before you enter the curve.

Not quite. The answer is Much of the tanker's weight is high up off the ground.

An object with a high center of gravity is top-heavy; much of its weight is high off the ground. Top-heavy objects are more prone to toppling over. Loaded tankers tend to have a high center of gravity because the tanks are so tall. This makes liquid tankers more prone to rolling over. Tests have shown that tankers can roll over on curves even at the speeds posted. On curves, slow down well below the posted speeds.

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 Slow to a safe speed before entering, then accelerate slightly through the curve.

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. Braking in a curve risks a skid.

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 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 At the start of each trip and each time you stop

If you have a placarded trailer with dual tires, you should check the tires at the start of each trip and each time that you stop for any reason, whether to rest or to refuel. Use a tire pressure gauge to get an accurate reading.

Not quite. The answer is You will continue in a straight line and keep moving forward no matter how you steer.

In a front-wheel skid, the front end of your vehicle tends to travel in a straight line regardless of how you turn the steering wheel. This type of skid is most often caused by driving too fast for the current driving conditions. Therefore, the best way to recover from this type of skid is to just let the vehicle slow down. Steer and brake only gently.

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 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 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 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 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 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 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 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 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.