Cars need not carry their fuel with them, as already discussed. Even if they do, battery technology improves constantly.

Great. And they're still more wasteful than a train. Which means more load on the grid, something that can't be tolerated on a green grid. And carrying a battery means that it still has to carry its fuel with it - batteries aren't weightless, you know. I'm willing to bet they still can't even come close to oil in terms of energy density. And then there's all the problems with disposing of batteries that've exceeded their lifespan...

And you still haven't dealt with the congestion and safety issues.

"Think about the way you drive" doesn't prove anything, because we shouldn't be talking about future perfect trains compared to today's cars.

Actually, we're talking about modern trains compared to near-future cars. And the way one drives is very relevant - cars are inherently human-controlled free-route vehicles. This introduces certain inherent inefficiencies that trains don't share because they travel a closed, fixed route.

Also, I don't see what's wrong with waving a technological wand around. Is there some problem with thinking that technology--of both cars and trains--will change in years to come?

Yes, there is. We're running out of oil. We need to develop replacements for oil-dependent methods. In most cases, this means drastic changes to the way we do things, because our current oil-centric methods are inherently wasteful in many ways. All of the alternatives have a significantly lower energy density. One can't just wave the magic technology wand and say "cars will continue to be viable". There's only so much technological developments can do before you start running into limits caused by the basic characteristics of the mode of transport.

This is not a political statement, nor is it a decision. The purpose of this diary series is not to "decide" anything, but to examine the options available to a post-oil society (which ours will be in about fifty years) based on current technology. Any subsequent technological developments, except possibly the development of economically viable fusion power, will only shift things further in favour of the alternatives presented here.