This chapter focuses on the decision-support process for transportation, beginning with a look back to the antecedents of current practices in transportation planning and decision making. It then reviews the current process and concludes with recommendations on the “who, what, and why” of informed transportation decision making for livable communities.

An improved decision-support process—including both data and tools—will help focus attention on the real consequences of transportation investments within communities. Improved data will aid broader consideration of often narrowly defined transportation consequences— for example, better transit access to major attractions, enhanced goods movement, shorter travel times—and foster more insightful consideration of the socioeconomic, land use, and environmental factors that help shape a community’s livability. These factors include mobility and equity consequences across locations within a region and across stakeholder groups; impacts on land use and development patterns and the consequences of those development patterns; the interaction of transportation operations with the natural and built environments, and impacts on sustainability; distribution of economic benefits and costs spatially and demographically; and consequences for community cohesiveness and character.

As communities, transportation planners, and decision makers have sharpened their understanding of the links between transportation and livability, the list of questions to be considered in making transportation