Environmental engineers and planners rely on GIS to meet increasingly stringent regulatory requirements for highway development. GIS enables planners to create a digital record of observed field data and design data such as wetland status or endangered species inventories along with route alignments (cut/fill area). This digital record simplifies future data gathering efforts and enables more reliable impact and trend analyses. This paper will focus on how ARC/INFO and ArcView GIS software were used to streamline and improve highway planning for a 30-mile segment of the Maine Turnpike Authority.