Because heaven knows gasoline isn't flammable.
The U.S. have more than a million hydrogen powered vehicles by 2020. If the goal was 2010 or something it would be interesting.
Hydrogen is much more volatile. They will need to ensure they have excellent containment systems. You don't mess w/this stuff.
Liquid gasoline is not flammable. Gasoline vapors are. You can actually put a match out in gasoline if you move it through the vapor layer quickly enough.
Gasoline leaking from a car wreck rarely ignites. Hydrogen leaking from a car wreck will frequently ignite with a flame that is nearly invisible.
Oil rig workers who are walking the pipes will often hold a broom handle in front of them. If the handle suddenly cuts in half, they know they've stumbled on a hydrogen fire.