A dispatcher offers a driver a choice between hauling a partially filled tank or a completely full tank of the same liquid over the same route. Based on what causes surge, which load presents the greater surge-handling challenge?

49 CFR § 383.119(a)/(b) (causes of cargo surge; stopping techniques when a tank is full, partially filled, or empty); AAMVA CDL Manual §8.2.2, p.8-8-1

Route and load-planning decisions should account for the fact that partially filled tanks carry a distinct surge risk that full tanks don't share in the same way. Drivers hauling partial loads need to adjust their braking and acceleration habits accordingly. This concept is directly tested under the federal tank vehicle endorsement knowledge requirements.