Traditional Neighborhood Development (TND), also called Neotraditional Development or the New Urbanism, refers to a pattern of land planning and development that emulates the towns and suburbs built in the early to mid-20th century more than the automobile-dominated suburbs of the 1960s and beyond. While the typical suburbs and planned communities built since the 1960s have stressed a separation of uses and great emphasis on the automobile, traditional neighborhood development stresses a walkable scale, an integration of different housing types and commercial uses, and the building of true town centers with civic uses.
The idea of returning to the traditional neighborhood form arose in the 1980s and grew in popularity in the 1990s. What has led to this vision is a dissatisfaction of some people with some of the by-products of several decades of suburban development patterns. Separation of uses, over-reliance on the automobile, traffic congestion, and social isolation are among the problems that New Urbanism is proposing to solve. The historic antecedents of TNDs are old towns such as Alexandria, Virginia, as well as early suburbs such as Roland Park in Baltimore, Mariemont in Cincinnati, and Pasadena, California, while the antecedents of the new towns and PUDs of the 1960s and 1970s (Columbia, Maryland, for example) were the English Garden Cities and the Greenbelt towns in the U.S.
What is a Traditional Neighborhood Development? Generally, it refers to a project that has a mix of uses and an integrated mix of housing types and price ranges (rather than different products being separated into "pods"); an interconnecting street network (rather than a reliance on cul-de-sacs); a town center, formal civic spaces and squares (rather than informal or "leftover" open spaces); and pedestrian oriented design that pushes garages to the rear of house lots and places parking lots behind buildings instead of in front of them. According to the September-October 1998 issue of New Urban News, there are now 97 TNDs in the U.S. that are built or under construction, and another 104 in the planning stage. This includes suburban developments as well as central city developments. Those that are substantially built and have garnered the most national attention are Kentlands (Gaithersburg, MD), Seaside (Florida), Harbor Town, (Memphis, TN), Celebration (Florida), and Laguna West (Sacramento County, CA). More recent projects include Riverside (in Atlanta); Addison Circle (near Dallas); and Redmond Town Center (in Redmond, Washington).
Many zoning and subdivision ordinances do not permit the development of TNDs because of the codes’ requirements for large lots, large setbacks, wide streets, and separation of uses. In some cases, Planned Unit Development ordinances have been used to build TNDs, but now more and more localities are adopting specific TND ordinances. Approximately 40 local governments have adopted codes permitting and promoting traditional neighborhood development (see attached list).

Transit-oriented development refers to traditional neighborhoods built around transit stops, especially rail transit. The same attributes that make a TND—higher density, walkable scale, mix of uses—are good generators of transit usage. Low-density, dispersed suburbs cannot be well served by transit. Many people propose that building transit-oriented traditional neighborhoods can foster compact development patterns, support transit use, and provide increased choices to consumers, many of whom may choose to live or work near transit.

Additional Resources
List of Traditional Neighborhood Developments underway from New Urban News, September-October, 1998
List of communities with codes that permit TNDs in New Urban News, December 1998
Project examples: "Portfolio: Harbor Town, Memphis, Tennessee," Land Development magazine, Fall 1992; "Portfolio: Newpoint, Beaufort, South Carolina," Land Development magazine, Fall 1995.
TND zoning code from Belmont, North Carolina
Model TND zoning code written by DPZ Architects
The New Urbanism, Peter Katz. McGraw-Hill, Inc., 1994.
Traditional Neighborhood Designs – The TND Series, Volumes I, II, and III. (Plans for homes and other buildings for traditional neighborhoods.) HomeStyles Publishing, St. Paul, MN, 1997, 1998, 1999.
Transit Villages in the 21st Century, Michael S. Bernick and Robert Burke Cervero. McGraw-Hill, Inc., 1996.