Read an article a couple years back about a demo car Mazda built and tested. It used the rotary engine, which they claimed could run off of either gasoline or Hydrogen without any reconfiguration, so it could switch fuel on-the-fly. The car had two separate fuel tanks for both fuels, though the H2 tank was much smaller, providing only about 50mi of range.
Also, during the G.W. Bush presidency, H2-powered auto tech (either via direct combustion or H2 fuel cells) was being pushed by the Administration as the preferred "clean" technology. It has quite a few advantages over battery powered e-cars and hybrids, and several other major manufacturers were developing them. When the Administration changed, government subsidies dried up and were replace with subsidies of electric cars so the major manufacturers dropped development (or so I understand). One major advantage of H2 as a fuel source is that it can be produced ahead of time and stored indefinitely, even from other "green" sources of electrical power such as wind and solar. And H2 is actually not nearly as unstable as most people think (I might be mistaken, but I believe I read somewhere that gasoline vapor is actually more inflammable than hydrogen). Plus, filling up with H2 takes no more time than filling up your tank with gasoline, a clear advantage over pure electric cars. Finally, producing H2 is fairly simple; you could produce a system to generate and store it that would take up no more room than an ATM. Imagine having that in your garage (or at least just outside). It would take household electric current and overnight replenish the holding tank, so you always have a full tank ready at home.
