strong>By Lester R. Brown
Cars promise mobility, and in a largely rural setting they provide it. But in an urbanizing world, where more than half of us live in cities, there is an inherent conflict between the automobile and the city. After a point, as their numbers multiply, automobiles provide not mobility but immobility, as well as increased air pollution and the health problems that come with it. Urban transport systems based on a combination of rail lines, bus lines, bicycle pathways, and pedestrian walkways offer the best of all possible worlds in providing mobility, low-cost transportation, and a healthy urban environment.