We stand on the threshold of what can realistically be described as the largest and most important shift in transportation in a century. The benefits will be enormous: An 80+ percent reduction in the cost of transportation. Reduced pollution. Reduced stress and road rage. A dramatic decrease in accidents and traffic deaths. Gaining back time lost to commuting — and the associated increase in productivity. Freeing up two lanes on many urban roads by eliminating parked cars. Even the reclaiming of the space allocated to home garages.