And finally, hydrogen tends to go &#x27;foom&#x27;.<p>Compared to all the other ways in which you could propel a car hydrogen is a very dangerous one and that alone is reason enough why it probably will never happen. Compared to LPG for instance hydrogen is <i>much</i> harder on the system and much more dangerous to handle. I don&#x27;t see it happening any time soon.<p>Keep in mind that a lot of inner city parking space is indoors &#x2F; underground.