Conceiving alternatives

Recent concept cars explore solutions to fuel-supply and emissions concerns.

This year's auto shows in Frankfurt and Tokyo give the German and Japanese home teams a chance to demonstrate their technical savvy to the world, and this year's crop of concept cars focused on applying that savvy to environmental concerns.

The fundamentals of reducing fuel consumption and the resultant emissions of either smog-forming pollution or greenhouse gases are well known; move less mass, less forcefully, consuming less fuel.