Many commonly used methods to measure Environmental Justice (EJ) impacts of transportation improvements are based on the pre-definition, using a Geographic Information System (GIS), of analysis zones as protected or unprotected. Generally, a zone is defined as protected, for a specific minority, if the percentage of a given minority population is above a given value, typically the overall regional percentage. This approach not only ignores the impacts on minority populations that are located outside the defined protected zones but also relies on arbitrary criteria to define if a zone is protected or not. The method presented in this paper offers an alternative to measuring and comparing EJ impacts that considers all members of any given minority group that live in a region. The impacts and benefits are expressed as accessibility to opportunities, such as jobs, for a given range of travel time. Congestion level of the roadway network is also considered as a measure of EJ impact. The inputs of this analysis are the geographic referenced results of a travel demand model as well as the spatial distributions of minority groups. The application of this methodology provides an objective way to compare, at the regional level, the repercussion of two specified transportation planning scenarios or horizons for any minority group. The results can be easily visualized in thematic maps created in a GIS.
Samenvatting