Measuring the Regional Economic Impact of Transportation Access Improvements in the Context of a Large Metropolitan Region

Transportation planners are increasingly recognizing the importance of access in enabling employment growth and better paying job opportunities for residents. Although regional economic impact analysis is often an important element of transportation investment evaluation by state departments of transportation, it can be particularly challenging for metropolitan area planners because existing economic modeling methods do not fully account for the multifaceted roles that transportation links play in affecting access within large, polycentric metropolitan areas. This article examines these issues and presents information from a study of the Chicago region, to evaluate statistical relationships of employment cluster size and wage levels to zonal differences in business-to-business connectivity and population connectivity. It presents elasticities of employment and wage impact associated with various access measures for different sectors of the economy. These findings point to the importance of transportation planners considering the impacts on connectivity to both population markets and employment centers when evaluating the potential economic implications of proposed transportation system improvements in large, polycentric metropolitan areas. The article then lays out directions for future research and practice to improve transportation project evaluation and planning.