Not to mention the danger of storing liquid hydrogen. Can you imagine a chain reaction of exploding cars, say, on the freeway into L.A.?
True. The tanks won't be compressed gas.
My understanding is that there has been a lot of advance in storing hydrogen in sponge like materials to which it weakly bonds in a hydride form and can be easily extracted in the vehicle using a catalyst.
In many ways it is like a ni-cad battery only instead of extracting electricty one extracts hydrogen, and then periodically re adds it.
The major problems are weight and size (currently about 3x as big as a gas tank and 6x as heavy), cost (metals used as the sponge may be expensive not to mention the catalyst), and safety.
The big push is for the tank to store about 50% of its weight in hydrogen. At that point you probably have something commercially feasible.
Liquid is so much better. Has anyone heard of a BLEVE?
Boiling Liquid Expanding Vapor EXPLOSION!