Executive Order 12898 requires federally sponsored transportation projects to evaluate environmental justice criteria. These federal requirements for transportation studies have proven difficult to evaluate because of the wide range of potential scenarios that can disproportionately affect sensitive populations (either low-income or minority groups). Therefore, environmental justice assessments typically have been conducted in geographically broad areas without refined resolution for the populations closest to the transportation route. This study uses geographic information systems technology with statistical methods to provide for a more refined analysis at the census block level. The study centers on a proposed commuter rail project in the Interstate 35 corridor in the eastern Kansas/Kansas City, Missouri, area. The project involves construction of five new commuter rail stations, and the study aims to ascertain whether construction and operation of the rail system would have disproportionate impacts on low-income people. Comparisons of the median incomes in census blocks in the county with the census blocks within a one-mile radius of the five proposed stations are provided as the basis for a quantitative environmental justice assessment. The environmental justice parameter of low-income level was evaluated using analysis of variance. Results of the study indicated that the mean of the median incomes in census blocks around one rail station differed significantly from the mean of median incomes in the census blocks around the other four stations, and from the blocks in the rest of the county. The study is useful for demonstrating the importance of using a quantitative method as a tool for environmental justice assessment.