The study limits are set based on the issues the corridor planning project is trying to address. It is suggested to consider the overall project location and intersections, interchanges, segments, or other facilities (frontage roads, parallel routes) that will be included in the analysis. The broader study area often includes the corridor/route/parallel routes that are being studied, along with larger demographical areas such as cities, counties, and TxDOT Districts. The purpose of the larger area surrounding the corridor/route is to provide additional context on the characteristics of the area, such as traffic patterns, environmental features, population, Gross Domestic Product (GDP), land use, employment, industries served, freight movement, and other points of interest.