You are driving a tanker with a partially filled cargo tank and you come to a stop. What happens inside the tank, and how can it affect your truck?

49 CFR 383.119(a) (knowledge of causes, prevention, and effects of cargo surge on motor vehicle handling); AAMVA CDL Manual Section 8.2.2, pp.8-8-1 to 8-8-2 (the surge description begins on page 8-8-1 and the 'wave hits the end of the tank' clause continu

Liquid surge is one of the most counterintuitive hazards in tank vehicle driving because the cargo keeps moving even after you start braking. If you don't anticipate the wave hitting the end of the tank, it can push your truck in an unexpected direction right when you're trying to stop. This mechanic is the foundation for nearly every other tank-driving safety rule.