"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." –Lester R. Brown, Plan B 4.0: Mobilizing to Save Civilization.
Lecture by Lester Brown at Google headquarters. Topic: Plan B: Rescuing a Planet Under Stress and a Civilization in Trouble. Watch the video.