Vic Smith wrote:

Don't know about storage. Others are citing rules.
I keep plastic 5 gallon, 2 gallon and 1 gallon containers in my
garage, tucked away under the workbench. One of each.
The 2 gallon is for filling the lawn mower.
Easy to handle and not spill gas.
The 1 gallon has the 2-cycle mix for the weed whacker.
The 5 gallon only comes out to replenish the others.
As to your question, the simple answer is one at a time.
No reason you have to transport all the gas at once.
Though I don't see moving 4 5-gallons jugs in the trunk as an issue if
they are reasonably secured and you don't travel far.
But I'm less than half a mile from a gas station.
If I had to travel more than a couple miles I'd probably carry one at
a time.
When I do the yearly half-mile trip with my 3 jugs it's a dedicated
trip and I'm aware of what's in the trunk the entire time.


We kept 5 gallons of gas on hand to replenish the 6-gallon tank on the
generator. Seemed sufficient.

Then Hurricane Yikes came along and knocked 4 million people in our city
into the no-power zone, including every gas station for fifty miles! For TEN
FREAKIN' DAYS!

I now have a LOT of six-gallon gas cans.

The next time a hurricane heads this way, I'm gonna fill every blessed one
of them! I'll stack 'em in the garage along with lawn chairs, pot plants,
garbage cans, the dog, and anything else that might blow away in 80 mph
winds. If the door-to-door gas-can inspector comes by, I'll lie or plead
exigent circumstances.