Harvey J. Miller

Transportation-planning researchers have long argued that the end goal of a transportation system is increasing accessibility, or opportunities for individuals to meet their daily needs, but that US practice tends to focus on increasing mobility, or opportunities to travel farther and faster. This study finds evidence that the gap between theory and practice may be closing when it comes to accessibility, but that significant barriers still exist to the wider adoption of the accessibility paradigm among metropolitan planning organisations, the main entities responsible for regional transportation planning in the USA. We measure this gap by creating an accessibility index based on content analysis of a nationally representative sample of 42 US regional transportation plans (RTPs). We then use regression-tree analysis to determine the characteristics of metropolitan areas that are most likely to employ accessibility concepts. Finally, we identify barriers to a wider adoption of the accessibility paradigm. Most RTPs include accessibility-related goals, but few define the term or use accessibility-oriented performance measures. The lack of clarity on accessibility leaves vehicle speed as the fundamental criterion for success in most plans. Our analysis finds that MPOs serving large regions with high per capita income are the most likely to produce plans that focus on accessibility. We argue that such places produce more accessibility-oriented RTPs because they have greater planning capacity and recommend changes to federal planning guidelines that could speed the adoption of the accessibility paradigm in RTPs.