What kind of volume would you guys think youd need to totaly run your car on hydrogen with a preasure system. Ive seen some systems that have a 10,000 psi holding tank that gets on average of 300 miles to a fill but thats on a compact. Id say the tank looks like a 10 gallon. Its highway leagal and impact safe with a switch that shuts the tank off, probly hooks up to the same system as the airbags. The only drawback of burning hydrogen is water after burn and whats needed to be done to purge the engine before shutdown. With what im using I just shut the hydrogen off for a minute. Im thinking of trying a system like that on my mazda after it gets out of the body shop. I figure after the initial cost alls you need to do is plug it in when you get home and not go more then the gas range. Check these out

http://www.qtww.com/products/afsch/injectors.php