"The American dream is absolutely changing," he told CNN.
This change can be witnessed in places like Atlanta, Georgia, Detroit, Michigan, and Dallas, Texas, said Leinberger, where once rundown downtowns are being revitalized by well-educated, young professionals who have no desire to live in a detached single family home typical of a suburbia where life is often centered around long commutes and cars.
Instead, they are looking for what Leinberger calls "walkable urbanism" -- both small communities and big cities characterized by efficient mass transit systems and high density developments enabling residents to walk virtually everywhere for everything -- from home to work to restaurants to movie theaters.
The so-called New Urbanism movement emerged in the mid-90s and has been steadily gaining momentum, especially with rising energy costs, environmental concerns and health problems associated with what Leinberger calls "drivable sub-urbanism" -- a low-density built environment plan that emerged around the end of the Second World War and has been the dominant design in the U.S. ever since.
Thirty-five percent of the nation's wealth, according to Leinberger, has been invested in constructing this drivable sub-urban landscape.
But now, Leinberger told CNN, it appears the pendulum is beginning to swing back in favor for the type of walkable community that existed long before the advent of the once fashionable suburbs in the 1940s. He says it is being driven by generations moulded by television shows like "Seinfeld" and "Friends," where city life is shown as being cool again -- a thing to flock to, rather than flee.