I wonder if any one has calculated the net effect of using hydrogen made from fossil fuel instead of using fossil fuel running a car? If we use less fossil fuel (and lass polution), it's good. Even if the net effect is zero, it's still good in terms of polution if the hydrogen plants are not in a crowded city. Only if we use more fossil fuel to produce hydrogen to drive the same distance as we use fossil fuel directly, we should be worried.