Gil Penalosa in this TEDx talk highlights the importance of the need to stop building cities as if everyone were 30 years old and athletic. If this is taken into account then you end up following the example of some of the best cities in the world, such as Copenhagen and New York city. But this requires urgent action and has to be undertaken by people with political vision, and the will power which requires strong leadership. Gil also goes on to mention that public participation is also a key aspect. Check out the full TEDx talk.