Wow, these things are expensive.

Just to clarify: the regular storage cans (like the same company, Justrite's type II storage cans) release vapors automatically. This is good for storage (prevents pressure buildup) but not so good for transportation since if release occurs while in the car, it will smell and may possibly ignite. So they can be used for short distances only, like from the gas station home. Whereas these DOT-approved cans can be locked to prevent release while in transport. So they won't smell in the car and you can take them somewhat more safely over long distances. Is that the idea?

How unsafe are the regular plastic cans? Say I had to evacuate. In an emergency situation, is it worth it to take a few cans in the trunk, or is it so dangerous that it's better to risk running out of gas?