I have a typical back yard, open mostly to the sun, where I store five
5-gallon jerry jugs of gasoline for my bikes and equipment and off-road
vehicles.

I don't see that it's all that much of a danger, considering we keep two
cars in the garage with twice that much gasoline essentially inside the
house - while this is outside along the fence.

But, my neighbor noticed the four jugs recently and asked about them. I
said I never knew gas to spontaneously explode and he said the sun could
cause it to happen. He also said it's illegal to transport more than a
single five-gallon can in your trunk (is that true?).

Is it all that dangerous to keep 20 gallons of gas in the back yard?
Is it illegal to trasnsport more than 5 gallons (California) in a car?