Alaska Tanker CDL Practice Test

How do baffles inside a liquid tank help control liquid movement?

• Controlling both forward and backward liquid surges
• Reducing the speed of the truck
• Stopping side-to-side liquid surge

Correct answer: Controlling both forward and backward liquid surges

Liquid in a partly filled tank moves as a wave. When the wave hits the end of the tank, it pushes the truck the same way. Baffles are bulkheads with holes in them. The liquid must flow through the holes, so it slows down. This controls the forward and backward surge and helps you keep control when you start and stop. Baffles do not stop side-to-side surge, so a tanker can still roll over in a curve. Baffles do not slow the truck down; you do that with your brakes and by slowing before curves.

When filling up a tanker with 3 or 4 valves at its bottom, how should you position the valves?

• Locked
• Secured
• Closed

Correct answer: Closed

When filling up a tanker with 3 or 4 bottom valves, make sure those valves are tightly shut. This prevents any spills or leaks while loading.

When filling up and emptying tanks with bulkheads, the driver needs to ensure the weight is evenly distributed.

• TRUE
• FALSE

Correct answer: TRUE

Bulkheads divide one liquid tank into several smaller tanks. You fill and empty those smaller tanks one at a time, so the weight can pile up on one end of the vehicle. Watch the weight distribution as you load and unload each compartment. Neither the front nor the rear should carry too much weight. Balance the load from front to rear before you drive. FALSE is wrong because the bulkheads hold the liquid apart, but they do not spread the weight for you.

On all tank vehicles, what is the most important item to check for?

• Cracked hoses
• Leaks
• Broken seals

Correct answer: Leaks

A leaking tank spills its load onto the road. That can cause a crash or serious environmental damage, so leaks come first on every tank inspection. Look under and around the vehicle for any sign of leaking before you load, unload, or drive. Never drive a leaking tank. Doing so is a crime: you will be cited, stopped from driving further, and you may have to pay for the cleanup. Cracked hoses are tempting to pick, but you check pipes, connections, and hoses for leaks — the leak is what you are looking for.

What must a tank truck driver understand about the posted speed limits for curves?

• Tank trucks have a higher center of gravity.
• The posted speeds may not be slow enough for a tank truck.
• A rollover can still occur when traveling at posted speeds in a tank truck.
• All of the above.

Correct answer: All of the above.

All three statements are true, and each covers only part of the risk, so All of the above is right. A tank truck carries a lot of its weight high above the road. This high center of gravity makes it top-heavy and quick to roll over. For that reason, the speed posted for a curve can be too fast for a tanker. Testing has shown tankers rolling over at the posted curve speeds. So obeying the posted number does not prevent a rollover. Slow down before each curve. Take highway curves and on-ramp and off-ramp curves well below the posted speed.

A tank endorsement is required for certain vehicles that transport what?

• Liquids or gases
• Oversize loads
• General freight in boxes or pallets

Correct answer: Liquids or gases

You need a tank endorsement to drive certain vehicles that carry bulk liquid or gas in a tank. The cargo can be any liquid or gas, hazardous or not. In a tank that is only partly full, the liquid shifts when you brake or turn. The load also sits high above the road. Both make the vehicle top-heavy and likely to roll over. That is why tank drivers must pass a special knowledge test about large liquid loads. Oversize loads and boxed or palletized freight are not carried in a tank and do not surge. They do not need a tank endorsement.

How do wet roads affect the normal stopping distance of a tank vehicle?

• They add only a few feet to it.
• They do not change it.
• They double it.

Correct answer: They double it.

A tank vehicle already needs a lot of room to stop, because the liquid surge makes hard stops dangerous. The handbook's stopping-distance rule says wet roads double the normal stopping distance. So on a wet road, slow down, brake far in advance, and leave about twice the space you would leave on a dry road. Adding only a few feet of space is not enough, and thinking the distance does not change is the most dangerous mistake.

Why must you know how much outage each liquid you haul requires?

• Different liquids expand by different amounts, so each one needs a different amount of outage.
• All liquids expand by the same amount, so each one needs the same amount of outage.
• Outage matters only when the tank has no baffles, so a baffled tank needs none.

Correct answer: Different liquids expand by different amounts, so each one needs a different amount of outage.

Liquids expand as they warm. If you fill a tank to the very top, the warming liquid has nowhere to go and it forces product out. Outage is the empty space you leave for that expansion. Different liquids expand by different amounts, so each one needs a different amount of outage. Leave enough that the tank will not be full at 130 degrees Fahrenheit. Baffles do not change this. Every liquid expands as it warms, so you never load any cargo tank totally full.

During loading, what should be the position of the tanker's manhole covers and vent covers?

• Closed without their gaskets
• Closed correctly
• Tightly sealed with tape

Correct answer: Closed correctly

Manhole covers and vents are where a tank leaks first, and leaks are the most important thing you check on a tank vehicle. So each cover must have a gasket and must close correctly. Keep the vents clear so they still work. Never drive a tank vehicle with open valves or manhole covers, and close all manholes and valves before you move the tank, no matter how short the trip. Manholes and valves must be closed to prevent leaks. A cover without its gasket cannot seal, and tape would block the vents that must stay clear.

What do you call the walls inside a tanker that have holes to let the liquid flow through?

• Smooth bores
• Baffles
• Partitions
• Barriers

Correct answer: Baffles

Baffles are bulkheads inside the tank with holes that let the liquid flow through. The holes slow the wave, so the liquid cannot slam into the end of the tank when you start or stop. That is why baffles control forward and backward surge. Take care in turns: side-to-side surge can still occur, and it can roll the vehicle over. A plain wall that divides a tank into smaller tanks is a bulkhead; it is a baffle only when it has holes.

Stop valves in a cargo tank:

• Are controlled remotely
• Close in an emergency
• Open automatically during maintenance
• Protect the tank and piping from rear-end collisions

Correct answer: Close in an emergency

Stop valves in a cargo tank are special parts that close automatically in an emergency to prevent spills.

You are driving at night with your high beams on. When must you dim them?

• Within 250 feet of an oncoming vehicle, and within 100 feet of a vehicle you follow
• Within 500 feet of an oncoming vehicle, and within 200 feet of a vehicle you follow
• Within 500 feet of an oncoming vehicle, and within 500 feet of a vehicle you follow

Correct answer: Within 500 feet of an oncoming vehicle, and within 500 feet of a vehicle you follow

Glare from your high beams can blind drivers coming toward you. It also bothers drivers ahead of you when your lights shine in their rearview mirrors. So dim your lights before they cause glare. Dim them within 500 feet of an oncoming vehicle and when you follow another vehicle within 500 feet. The distance is the same in both cases. A shorter distance for the vehicle ahead is wrong, because your lights still reach its mirrors. When no vehicle is within 500 feet, use your high beams if it is safe and legal.

Why should you check the intake, discharge, and cut-off valves before you load, unload, or move the vehicle?

• To confirm the valves are properly labeled
• To ensure they are in the correct position
• To make sure the valves are open before you drive

Correct answer: To ensure they are in the correct position

A valve in the wrong position leaks. An open discharge valve can spill product onto the road or onto the loading area. So you check the intake, discharge, and cut-off valves, and you set each one correctly before you load, unload, or move the vehicle. Never drive a tank vehicle with open valves or manhole covers. Leaks are the most important thing to look for on a tank vehicle. Carrying liquid or gas in a leaking tank is a crime: you can be cited, stopped from driving, and made to pay for the cleanup. A label does not tell you whether a valve is open or shut.

You are driving a tanker, and an oncoming driver has drifted into your lane. Which move is best?

• Steer to your right, away from the other driver.
• Steer to your left, into the other driver's lane.
• Stay in your lane and brake as hard as you can.

Correct answer: Steer to your right, away from the other driver.

The other driver will most likely notice the mistake and return to his or her own lane. If you steer left into that lane, you could meet head-on. So when an oncoming driver drifts into your lane, a move to your right is best. You can almost always turn to miss something faster than you can stop. In a tanker, do not brake while you turn and do not turn more than you need, because the high center of gravity makes a rollover easy. Braking as hard as you can risks locked wheels and a skid.

What should you inspect the tank's body or shell for?

• Leaks and discoloration
• Cracks and rust
• Dents and leaks

Correct answer: Dents and leaks

Leaks are the most important thing to check for on any tank vehicle. So go along the body or shell and look for dents or leaks, and check under and around the vehicle for signs of leaking. Never haul liquid or gas in a leaking tank. That is a crime. You will be cited and prevented from driving further, and you can be billed for cleaning up the spill. Rust, cracks and a change in color are not what this check is about. You are looking for dents in the shell and for any sign of product escaping.

What is a smooth bore tank?

• A liquid tank without baffles
• A tank designed for compressed gases
• A dry bulk cargo tank
• A liquid tank with baffles that control forward and backward surge

Correct answer: A liquid tank without baffles

Baffles are bulkheads with holes inside a liquid tank. They control the forward and backward surge. A smooth bore tank has no baffles, so nothing slows the liquid down. The forward-and-back surge is very strong, and the wave can push your vehicle when you start and when you stop. Drive slowly and carefully. Most smooth bore tanks carry food products such as milk, because sanitation rules forbid baffles that are hard to clean. The term describes what is inside the tank — not gas, not dry bulk, and not a tank with baffles.

When should you be extra careful driving a smooth bore tanker combination?

• When the tank is completely full
• While descending a hill
• When starting and stopping
• When loading or unloading

Correct answer: When starting and stopping

A smooth bore tank has nothing inside to slow the liquid down. So the forward-and-back surge is very strong. When you start or stop, the liquid runs the length of the tank as one wave. When the wave hits the end, it pushes the truck the way the wave is moving. On ice it can even shove a stopped truck out into an intersection. Brake far in advance, keep steady pressure on the brakes, and start gently. A hill is not the special risk here. The surge builds when your speed changes.

Which of the following statements about tanker vehicles are true?

• A big share of the load's weight rides high above the road.
• Tankers can turn over at the speed limits posted for curves.
• Both of the above.

Correct answer: Both of the above.

In a tank vehicle, a large share of the cargo weight sits high above the road. This high center of gravity makes the vehicle top-heavy, so it rolls over easily. Liquid tankers are at extra high risk of rolling over. Testing has shown that a tanker can tip over even at the speed posted for a curve. The posted number is not a safe speed for a tanker. On highway curves and on entrance and exit ramp curves, drive well under the posted speed. Both statements are true, so picking only one of them gives an incomplete answer.

What should you do before you load, unload, or drive a tanker?

• Fill the tank completely full.
• Open the manhole covers before you drive.
• Inspect the vehicle.

Correct answer: Inspect the vehicle.

You inspect a tanker before you load, unload, or drive it. The inspection shows you the vehicle is safe to carry the liquid and safe to drive. Leaks matter most. Check under and around the vehicle and look at the tank shell. Check the intake, discharge, and cut-off valves. Check the pipes, hoses, manhole covers, and vents. Carrying liquid or gas in a leaking tank is a crime. You can be cited, stopped from driving, and made to pay for the cleanup. Never load a cargo tank totally full, and never drive with open manhole covers.

Compared with loaded trucks, empty trucks:

• Are easier to control during sharp turns
• Have better traction than loaded ones
• May require longer stopping distances than full ones

Correct answer: May require longer stopping distances than full ones

An empty truck may need more distance to stop than a full one. A heavy vehicle's brakes, tires, springs, and shock absorbers are built to work best when it carries a full load. Traction is the friction between the tires and the road, and an empty vehicle has less of it. When a combination vehicle carries little weight, its very stiff springs and strong brakes leave the tires with poor grip. The wheels then lock up very easily. So leave more room to stop when you drive empty. Less traction also means less control in a turn, not more. Without traction, you cannot steer or brake.