California CDL: Tanker Vehicles Practice Test

Not quite. The answer is joints.

When you're checking the pipes, connections, and hoses of your tank vehicle for leaks, you should pay special attention to joints. Pipe joints are among the weakest points in a piping system. Joints can deteriorate over time and start to leak.

Not quite. The answer is your vehicle may jackknife.

If your drive wheels are skidding, it's likely because you applied the brakes too hard and locked the drive wheels. A drive-wheel skid can let the trailer push the tractor sideways, causing a sudden jackknife. To recover from this type of skid, the first thing to do is stop braking. The drive wheels will unlock and start to roll again.

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 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 20 mph

If you've moved onto a shoulder that may have a loose surface, let your vehicle slow down to about 20 mph before you brake. Braking at a higher speed on a loose surface can cause a skid.

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 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 If it has to stay very clean

For transporting food products such as milk, regulations prohibit baffled tanks because of the difficulty of cleaning the inside of a baffled tank.

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 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 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 Watch gauges and mirrors and use your senses to check for problems.

During your trip, you should be watching a number of things, such as your mirrors, gauges, instruments, lights, tires, and cargo. Use several of your senses – sight, hearing, smell, and feel – to detect possible trouble.

Not quite. The answer is 1,000 gallons or more.

Federal regulations define a "tank vehicle" as a commercial motor vehicle designed to transport liquids or gases within tanks that have an individual rated capacity of more than 119 gallons each and an aggregate rated capacity of 1,000 gallons or more. To drive such tank vehicles, you must have a Tank (N) endorsement or Combination Hazmat and Tank (X) endorsement on your CDL.

Source: 49 CFR § 383.5

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 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 roll over.

Baffled tanks can control back-and-forth surge but not side-to-side surge. During sudden steering changes, side-to-side surge can cause your tanker to roll over. Avoid such sudden moves when possible.

Not quite. The answer is bulkheads.

Separators that divide a space into liquid-tight compartments are called bulkheads. The tank on a tanker vehicle may have bulkheads to divide the tank into separate compartments.

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 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 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.