More than 30 years have passed since the Federal-Aid Highway Act of 1962 created the federal mandate for urban transportation planning in the United States. The act was the capstone of two decades of experimentation and development of urban transportation procedures and institutions. It was passed at a time in which urban areas were beginning to plan National Interstate and Defense Highway System routes through and around their areas. The 1962 Act, combined with the incentive of 90 percent federal funding for interstate highway projects, caused urban transportation planning to spread quickly throughout the United States. It also had a significant influence on urban transportation planning in other parts of the world.
In some ways, the urban transportation planning process and planning techniques have changed little over the 30 years. Yet in other ways urban transportation planning has evolved over these years in response to changing issues, conditions, and values and a greater understanding of urban transportation phenomena. Current urban transportation planning practice is considerably more sophisticated, complex, and costly than its highway planning predecessor, and it involves a wider range of participants in the process.
Modifications in the planning process took many years to evolve. As new concerns and issues arose, changes in planning techniques and processes were introduced. These modifications sought to make the planning process more responsive and sensitive to those areas of concern. Urban areas that had the resources and technical ability were the first to develop and adopt new concepts and techniques. These new ideas were diffused by various means throughout the nation, usually with the assistance of the federal government and professional associations. The rate at which the new concepts were accepted varied from area