"I heard of urea injection before, and joking aside, I thought it was nixed because it would place an unrealistic onus on the motorists to maintain an emission control fluid in addition to all the other drive train fluids. Not to mention it being one more thing you would have to buy in addition to fuel that gets more expencive all the time. Enforcement could also be a problem."

Well it hasn't been nixed unfortunatly. Every one of your points is a valid one. Unforunatly not much else to say about that. There have been "solutions" to those problems you mentioned but I don't think they are what everyone wants.

I've done some work in hydrofuel cells and alternative energy in general. I am not sure that hydrogen is the best solution, but I can't blame you for trying and doing your own research. I don't have time to read that entire thread, but it seems like an interesting idea and certainly worth a try. Play it smart, and you have nothing to lose and potentially lots to gain.

Good luck!!