It’s one of America’s longest and most iconic love affairs, but even our most innovative approaches to sustainable transportation are futile if we can’t forget our irrational obsession with the open road.

Question: Can cars ever be fully sustainable?

Felix Kramer: When we talk about cars and making cars cleaner, cheaper and so forth we don’t forget about the fact that we also want to reduce the use of cars. Every solution that involves alternative fuels, alternative energy has to start with conservation, using less, so in the United States we’re the only country whose freight is mostly delivered by truck instead of by rail and we can change that. People… Many people own big vehicles because for a week or two a year they need to bring a… tow a boat or something. They can rent the car. I’m really encouraged about the growth or car sharing and that whole idea. Many people don’t need to own two or three cars. They can own one car and the second and third car can be rented. There are a lot of solutions like that and in the long term smart communities and planning growth so that people can walk to work or take public transit to work. We need a much better public transit system than we have, but right now Americans are wedded to their cars and we have a responsibility to make those cars much better.