SD CDL - South Dakota Commercial Drivers License Tank Vehicle Rules Questions and Answers — Questions and Answers
Question 1: You are driving a tank vehicle with baffled compartments. When making a turn, what type of liquid surge should you still be most concerned about?
- Forward and backward surge
- Side-to-side surge (Correct answer)
- Vertical surge against the top of the tank
- Baffles eliminate all types of surge
Correct answer: Side-to-side surge
Baffles are designed with holes to slow down the forward and backward movement of liquid (longitudinal surge). However, they do not prevent side-to-side (lateral) surge, which can push the vehicle sideways and increase the risk of a rollover, especially in a curve.
Question 2: What is the primary reason that 'smooth bore' or unbaffled tank trucks are used for certain loads, like milk?
- They are less expensive to manufacture.
- They create less liquid surge than baffled tanks.
- They are required for hauling all hazardous materials.
- Sanitation regulations require tanks that can be thoroughly cleaned. (Correct answer)
Correct answer: Sanitation regulations require tanks that can be thoroughly cleaned.
Unbaffled tanks are used for products like milk because sanitation regulations require tanks that can be completely and easily cleaned. Baffles create nooks and crannies that would be difficult to sanitize, potentially trapping old product.
Question 3: A driver is loading a dense liquid into a large tank. Even if the tank is not filled to its volume capacity, what is the most likely reason the driver must stop loading?
- The legal weight limit for the vehicle has been reached. (Correct answer)
- The liquid needs more outage space than less dense liquids.
- The vapor recovery system has activated automatically.
- The vehicle's high center of gravity becomes too unstable.
Correct answer: The legal weight limit for the vehicle has been reached.
Dense liquids are very heavy. A tank may be only partially full by volume, but the weight of the liquid can cause the vehicle to reach its maximum legal gross weight limit.
Question 4: The term 'outage' refers to which of the following when loading a liquid tank?
- The process of cleaning a tank after unloading.
- A power failure in the pumping equipment during loading.
- The empty space left in a tank to allow for liquid expansion. (Correct answer)
- The amount of liquid lost due to a minor leak during transit.
Correct answer: The empty space left in a tank to allow for liquid expansion.
Liquids expand when they get warm. 'Outage' is the empty space intentionally left at the top of a tank to accommodate this expansion, preventing spills and dangerous pressure buildup.
Question 5: You are driving a partially filled, unbaffled tanker and need to come to a stop. What is the greatest danger caused by liquid surge?
- The surge can cause the engine to stall.
- The surge can push the stopped truck into an intersection. (Correct answer)
- The surge can damage the internal lining of the tank.
- The surge can cause the front wheels to lift off the pavement.
Correct answer: The surge can push the stopped truck into an intersection.
When stopping, the liquid surges to the front of the tank. As it sloshes back, the wave can be strong enough to push the entire vehicle forward, potentially moving it into a crosswalk or intersection, especially on a slippery surface.
Question 6: Which of the following is a critical safe driving rule specific to tank vehicles due to their high center of gravity and the effects of liquid surge?
- Driving faster than the posted speed limit to minimize time on the road.
- Making sudden lane changes to avoid obstacles.
- Applying brakes hard and late when approaching a stop.
- Slowing down well before a curve and then accelerating slightly through it. (Correct answer)
Correct answer: Slowing down well before a curve and then accelerating slightly through it.
Due to a high center of gravity, tankers can roll over at speeds below the posted limit for a curve. The correct technique is to slow to a safe speed before entering the curve and then accelerate gently through it to maintain stability.
SD CDL - South Dakota Commercial Drivers License Tank Vehicle Rules Questions and Answers
You are driving a tank vehicle with baffled compartments.
When making a turn, what type of liquid surge should you still be most concerned about?