A Class A combination vehicle carries three separate tanks, each rated at 150 gallons, for a total aggregate capacity of 450 gallons. Does this configuration require a tank endorsement?

AAMVA CDL Manual, Section 8 (Tank Vehicles), p. 8-8-1; consistent with the 'tank vehicle' definition at 49 CFR 383.5

Drivers sometimes assume that splitting liquid cargo into several smaller tanks avoids endorsement requirements. Understanding that capacities are added together (aggregated) prevents a driver or carrier from misjudging whether an endorsement is legally required for a given load configuration.