“Bicycles are not only thermodynamically efficient, they are also cheap. The cost of public utilities needed to facilitate bicycle traffic versus the price of an infrastructure tailored to high speeds is proportionately even less than the price differential of the vehicles used in the two systems. In the bicycle system, engineered roads are necessary only at certain points of dense traffic, and people who live far from the surfaced path are not thereby automatically isolated as they would be if they depended on cars or trains. The bicycle has extended man’s radius without shunting him onto roads he cannot walk. Where he cannot ride his bike, he can usually push it.