Idaho CDL: Tanker Vehicles Practice Test

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 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 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 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 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 an unbaffled tank.

A smooth bore tank is another name for an unbaffled tank. Without baffles, there is likely to be strong forward-and-backward surge. Nevertheless, certain cargoes such as milk and other liquid food products must be transported in smooth bore, unbaffled tanks. Sanitation regulations forbid the use of baffles because they are hard to keep sufficiently clean.

Not quite. The answer is 20 feet long.

An ISO standard portable tank is a metal tank enclosed in a steel frame. The frame is 19.8556 feet (6.05 meters) long, 7.874 feet (2.40 meters) wide, and either 7.874 feet (2.40 meters) high or 8.374 feet (2.55 meters) high.

Not quite. The answer is Get out of your vehicle and away from the tracks.

If your vehicle gets stuck on a railroad track, get everyone including yourself out of your vehicle. Have everyone walk at about a 45-degree angle to the tracks in the direction from which you expect a train to approach. That way, if your vehicle is hit, none of you will be struck by flying debris. Once you've reached a safe location, call 911 or the telephone number on the railroad crossing sign.

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 There will be less front-to-back surge than in a smooth bore tank.

Bulkheads divide a tank into several smaller tanks. This will reduce forward-and-backward surge, making it less likely that surge will push your vehicle forward when you try to stop. However, when loading and unloading the smaller tanks, be sure to pay attention to weight distribution.

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 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 on slippery roads.

When you're coming to a stop, the liquid in the tanks tends to surge forward. If you're on a slippery surface, the surge may shove your truck forward into another vehicle or an intersection. Learn how your tanker handles in such situations.

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 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 the front or the rear

Bulkheads help separate the load. When loading such tanks, distribute the weight evenly. Avoid putting too much weight on the front or the rear of the vehicle.

Not quite. The answer is The posted speed for a curve may be too fast for a tank vehicle.

Tank vehicles have a high center of gravity. 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 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 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.