I believe it is completely impractical as an automotive fuel. Its physical properties make it too expensive to transport and store and its combustion properties make it a poor internal combustion engine (ICE) fuel. It works well in fuel cells but these are much better suited to stationary power applications than automotive applications.

For more information about hydrogen and its use, the US Department of Energy has published the College of the Desert's Hydrogen Technician's Manual:

In addition, other useful resources are: