The main goal of this paper is to investigate the impact of accessibility changes on the level of economic development in a given region. In this paper, we introduce several types of accessibility measures while economic development is quantified in terms of changes in income and employment. The study area consists of 18 counties in the New Jersey/New York region where we have observed changes in accessibility and economic development for the decade 1990-2000. Using multiple regression analysis, the results show strong and significant relationships between accessibility changes and economic development. The models presented in this paper provide empirical evidence for transportation planners relative to the economic impact of transportation capital investment.