If we are headed for a prolonged period of expensive oil, Americans will increasingly be faced with the self-imposed conservation of energy. The result will trigger the reshaping of our pattern of living. It may resemble something of a higher-density, publicdemanded transportation model-one that will have Americans driving less to their homes, workplace, shopping and leisure destinations, and using less space and energy to heat and cool our built environments. Sound foreign? Well, actually it is. One can look no further than our European counterparts who have been dealing with space and energy issues far longer than we have. Will Americans adopt European living standards? For the immediate future, the pace of change will not alter our landscape anytime soon. But if trends hold in place as they have for the past halfcentury, this question will be placed on future generations of Americans as our lifestyle alterations are likely to take decades-perhaps a generation or more-to fully integrate a planning model that will triumph over waste and sprawl and reset our urban environment agenda. The United States planning model is inverted from most European cities. It is premised on mobility and the need to have detached, separated homes; accessible not by public transport, but the automobile. Whereas Europe's suburbs are where the working class (often poorer populace) live, the inner core of most major European cities are where the affluent live. In contrast, America's inner cities are often still associated with crime, the ghetto and the working class poor. America will have to stare down its long-associated view that the inner city is a ghetto haven. Building an infrastructure that is safe, clean, is less costly to achieve in inner cities because it is already in place is the biggest asset the inner city has to leverage. Once political will deems it necessary to sustain the urban core of cities, it will require solving the public transport problem in America. And once there is sufficient density, the advantage of transit access becomes abundantly possible. While different today, our future population and demographic trends will eventually demand transitoriented development that resembles European centers.

The reasons why change will occur are numerous from a socioeconomic and political viewpoint but can be condensed into a few simple ideas. First, energy costs will only continue to escalate and the oil-producing countries will continue to sway influence over oil prices. Second, our lifestyle will be forced to change according to the times- America will begin to rethink and challenge its conventional wisdom: debunking the myth that purchasing a detached family dwelling in the suburbs will remain the great American dream. Third, our planning model is inverted-it runs against energy conservation- and it will take decades to overcome our 20th-century planning model that wove an intricate balance of interstate highway connectivity and post- WWII automobile dependency. Lastly, our overburdened, municipal budgets cannot keep pace with the sprawl and the concomitant need to build tenlane freeways for automobile traffic every decade in every major American city. Cities will begin recoiling from its sprawling tentacles by midcentury under the weight of its own congested freeways.

Curiously enough, one economic theory stipulates that the greater the cost of fuel, the more expensive it becomes to commute farther distances, and thus, the lower the values of homes will become in suburbia. The demand will begin falling off for suburban track homes and set up an effect that will drive downtown development. The signs are already here: For the vast majority of Americans who remain inextricably dependent on their cars to get to work, they are increasingly having difficulty paying for higher gas and, in return, increasingly left stranded on the fringes. Millions of Americans live in far-flung subdivisions built when gas was less than $2.00 a gallon. Our cars may become more efficient, but those subdivisions will remain more costly to operate than their counterpart, downtown dwelling units.

For certain, America will need to change its ideas on what constitutes an ideal lifestyle. This change will be precipitated by seismic shifts in demography, housing, infrastructure, energy consumption and, more importantly, how America views itself. As we celebrate our country's 232nd birthday this month, think not why we divorced ourselves from our European cousins. Rather, let us embrace the possibilities of the future by learning from our distant relatives so that we may set a new trajectory of sustainable urban environments.