According to the CDL manual, what three factors determine how much liquid a driver should load into a tank?

49 CFR 383.119(i) (operating practices and procedures not otherwise specified); AAMVA CDL Manual §8.2.7, p.8-8-2.

Loading a tank correctly is a calculation, not a guess: a driver has to balance how much the liquid will expand, how much it weighs, and the legal weight limit all at once. Getting this wrong can mean either an overweight citation or a tank with too little outage room.