Why plan for walkability

"Mobility is intrinsic to the quality of life experienced in cities. But for the past century, the car has dominated how we plan and grow our urban areas. We must now seize the opportunity to place people back at the heart of our cities and drive a human focused approach to the design of the built environment. With a growing desire to create more liveable streets, walkability should be used as a catalyst for developing sustainable, healthy, prosperous and attractive cities."

from: http://www.arup.com/cities_alive/towards_a_walking_world