Intersection construction cost functions for alignment optimization

A method for precisely formulating intersection construction costs including earthwork costs, right-of-way costs, and pavement costs is introduced in this paper. Intersection design characteristics are reviewed and intersection cost components are formulated. A highway alignment is described by parametric representation in space, and vector manipulation is used to find the coordinates of intersections and other points of interest. A simplified typical fill section is studied to obtain actual ground and road elevation coordinates that are crucial for setting the boundaries and computing the costs. Because estimating right-of-way costs requires identifying affected properties and structures in the vicinity of an intersection, two examples based on geographic information system (GIS) databases from Maryland and an artificial study area are presented to show how the developed cost functions can be used in real applications. The developed intersection construction cost functions can be incorporated in previously developed highway alignment optimization models that neglected the characteristics and costs of intersections.