Essentially, these vehicles -- which are some of the first in the world two use duel technologies -- were created by private companies and in additon to the hybrid function, these vehicles have a larger battery which has a 30-mile electric driving range. In other words, if you're driving less than 30-miles in a trip (before you can plug back in) then you wouldn't use a single drop of gasoline.
And as a small heads up to our most loyal readers, we're going to work on a video podcast of this event that promises to have some humor. Check back tomorrow for more. UPDATE (5/22/06, 11:10 AM): More pictures of this car's debut on Capitol Hill here.