THE TRANSPORTATION PLANNING PROCESS
Transportation planning is a basic function of many planning agencies, for adequate circulation traditionally has been a major planning goal. As practiced in the last several decades, particularly at the multijurisdictional level, it is perhaps the most elaborate and mathematically well-developed area of planning. The modern multijurisdictional transportation planning process represents a fusion of engineering, economics, and urban planning, all facilitated by modern computing equipment. The field in its present form was brought into being by a coincidence of forces shortly after the end of World War II. The rapid increase in automobile ownership and the suburban housing boom created a massive demand for increased highway capacity. The Highway Act of 1954 provided 50 percent matching grants for urban highways and funds for transportation planning. It also required planning as a condition of eligibility for the matching grants—still another example of the conditioning of the local planning scene by federal funding requirements. In 1956 Congress passed the National Defense Highway Act, which initiated the building of the Interstate Highway System (see Chapter 17). Federal legislation and funding thus set off a wave of highway building in the decades after the war. The digital computer, which was invented at the end of the war and became a practical planning tool a decade to a decade-and-a-half later, made it possible to "crunch" huge amounts of data and thus make feasible the modern style of highway planning.
The following pages focus on highway planning at the metropolitan level. At smaller geographic levels, the process is necessarily simpler and less mathematical. More than most other planning processes, transportation planning necessitates a multijurisdictional effort, as the flow of travelers is no respecter of municipal boundaries. Thus the same communities that may do their land-use planning in relative isolation will often be part of an area-wide metropolitan transportation planning process.