Conventional land use regulations divide communities into defined zones that limit activities within each zone based on the specific category of use. For those of us that have grown up in these defined zone areas, it may be a surprise to learn that such traditional methods of controlling land use has a major impact on residents' health. Traditional zoning regulations that divide communities into separate geographical areas based on residential, commercial, or industrial use have resulted in heavy reliance on automobiles to travel to and from each zone. As a result, people are walking less in their day-to-day activities. Studies show that the lack of physical activity contributes to problems such as obesity, high blood pressures, and stress that have a serious effect on peoples' health. A number of communities are changing their zoning laws to encourage a healthier lifestyle. While it is premature to evaluate whether these new zoning regulations are having the desired effect, this trend has the potential to profoundly change the design of where we work, shop, and live and how we interconnect with the larger community.

Zoning laws are a relatively new concept and became widely adopted only in the last century. Prior to that, the accepted view, based on common law, was that property owners had the unrestricted right to use their property however they saw fit, free from governmental control. The landmark case of Village of Euclid, Ohio v. Ambler Realty Co., 272 U.S. 365 (1926), decided by the United States Supreme Court, established that zoning laws were legal under the government's traditional police powers to promote the public's health, safety, and welfare. The underlying rationale for zoning laws at that time was to separate industrial uses with their noxious smells, effluent, noise, and intensity from residential neighborhoods in order to provide a cleaner, safer, and more healthy environment. Nearly all early zoning laws were adopted by cities that had a dense urban core and a mass transit system that allowed people to travel about in their day-to-day activities without an automobile, which were in their infancy at that time. Walking, sometimes combined with a trolley ride, was the primary mode of transportation to travel to and from work, stores, doctors' offices and schools.

The adoption of zoning laws, however, coincided with the rise of the automobile and the combination of the two not only created the acceptance of zone use segregation, but it also facilitated urban sprawl because, over time, the automobile became essential to get around town. Consider your normal commute - your kids' school, your workplace, the grocery where you shop, and the park where you take your dog are all likely in different areas...necessitating daily use of an automobile.

In cities with dense urban cores and the availability of mass transit, this effect is demonstrable. For example, according to a study done in 2008, one in four New York City residents is overweight but those people who live or work in Manhattan are thinner than residents in other boroughs. Manhattanites walk more to go to and from work, walk up steps, and walk to and from mass transit stops and are generally healthier and fitter than those in other parts of the city. However, there is no evidence that Manhattanites eat any less than their counterparts in other boroughs.

Many communities are now starting to review their own zoning regulations and adopt new laws that encourage a fitter lifestyle. The most far-reaching example of this trend is the rise of mixed-use zoning. While The Town of Euclid v. Ambler Realty upheld the concept of separating uses, mixed-use zoning blends them. Mixed-use zoning can take several forms, from allowing a mix of residential and nonresidential uses within the same building to allowing the mix of uses within the same area or overall project. In theory, mixed-use development would enable people to walk or bicycle between their residences, places of employment and shopping areas, thus reducing the need to drive to and from essential day-to-day activities.

Closely related to mixed-use zoning is the trend to encourage or even mandate higher density areas, particularly near downtown and in older parts of town that areproposed for redevelopment. Greenspace, such as parks, are typically coupled with higher density requirements in order to provide active and passive places for residents to enjoy. Sidewalks, which city planning agencies once considered optional, are now being required for all new developments. Similarly, governments are installing bicycle paths in parks and greenways and land use regulations now require new streets and roads to include designated bicycle lanes as part of a "complete streets" program. Mass transit is being encouraged with the adoption of zoning ordinances that allow developers to build non-automobile dependent improvements, such as regulations that provide a reduction in required parking to developers who are on a bus line or for those who install a covered bus stop to serve their development. Similarly, some cities give density bonuses or reductions in required parking spaces to developers who provide bicycle racks, as a means to encourage more bicycle use.

Some communities are encouraging healthy eating through the adoption of zoning ordinances that expressly allow farmers markets as a permitted use in areas with sizable residential populations, especially in areas with many low income or elderly residents that have less access to reliable automobile transportation. An increasing number of cities are allowing by right the keeping of a small number of chickens in residential backyards, and allow community gardens on vacant residential lots.

Time will tell whether communities will become healthier or fitter over time through the use of these new land use regulations, and the extent to which people will actually reduce their reliance on the automobile for day-to-day living. One thing, however, is certain: zoning laws are not static, but evolve in accordance with communities' visions for their future. The current trend goes back to the future, so to speak, because cities are rejecting the concept endorsed in Ambler to have a healthier, safer community by separating uses and are returning to the idea that mixed-use development and walkable integration of uses is the healthier alternative.