"Big John" wrote

Most tankers have multiple tanks. For example a 8000 gallon tank truck
could have four 2000 gallon tanks. This lets them deliver smaller
amounts of gas to the small Stop & Go type stores that don't want to
invest the dollars in a full load all at one time.

The multiple tanker layout is also a safety feature so that if one
tank starts a leak only part of the load will get out (small possible
fire and clean up and less money lost). Also it lets the tanker carry
different grades of gas (reg, super, extra $ super) on one delivery to
a station.

Also, it is VERY important to have dividers in a large tanker, so when you
are putzing about with a third of a load, that you don't have the whole load
shift to the front at one time, or back, or whatever.
--
Jim in NC