Just saw an article at knoxnews.com that can be found here.
To summarize, this former couch potato couple started to seriously walk and made their diets healthier. They made a point of walking 10,000 steps every day. The husband no longer needed a knee replacement, and was able to get rid of the blood pressure medication, while halving the cholesterol medication.
10,000 steps is around five miles. For most people dedicating an hour and forty minutes (assuming a walking speed of 3 mi/hr) every day to walking isn't practical; however, the 10,000 steps can include ordinary activities, making it much more manageable. A pedometer was suggested as a way to track the number of steps taken.
For short trips, walking is an eminently feasible way to get around, not to mention being relaxing and healthy. The construction of sidewalks around busier streets can greatly encourage this most basic form of transportation.