The primary concern is money. As much as I personally want to reduce my carbon footprint, I do need (and prefer) to drive sometimes and there is no way I could afford a new hybrid vehicle or conversion for my car right now. Maybe one day I'll be wealthy and can buy a new hybrid, but then what becomes of my vehicle? Isn't it best to use reduce the amount of plastics and metals we use? So it's a tough call, but I think I should use my current vehicle until it just can't go any more. And, since I hope it'll last at least another 5 years, I'm certainly hoping there will be newer, cheaper, better technologies available at that point.

You mentioned biofuels as an alternative to fossil fuels. In addition to the great cost of converting vehicles to run on biofuels, there are huge environmental concerns with this method. Corn is already a major crop in the United States, but we'd need to grow a LOT more if it were to be used in the majority of vehicles. What land are we going to use to grow it? Where is the water going to come from? I have a particular interest in the water aspect of this environmental issue and because of it I'm not at all convinced that corn products are a good alternative to fossil fuels on a large scale.

I only mean to point out some of the problems that come up when considering alternative fuels, but I do believe there needs to be a change. Part of the reason changes take time is purely political, but there are also many issues that need to be considered. It makes no sense to spend a lot of money to rush into a new technology and convert vehicles across the country only to realize a few years later that it created a new environmental problem.