Congress Avenue Regional Arterial Study: Grade Separations
Larry Lang and Randy Machemehl, University of Texas at Austin, June 1995, 126 pp.
This study describes a simple analysis for determining whether or not grade separation is warranted for intersections along urban arterial streets. This determination required the evaluation of user benefits attributable to operational and design improvements made to arterial intersections. Comparisons are made between grade-separated interchanges (GSI) and at-grade intersections (AGI) in terms of the delay, user travel-time costs, and vehicle operating costs. Overall, the justification for grade separation is dependent on the user benefits offsetting the interchange construction cost over an assumed design life. A discussion is provided on generalized warrants for grade separation and on methodologies, used by others, to justify such structures. Also, this study discusses numerous geometric design considerations for grade-separated interchanges and other roadway facilities.
Keywords: At-Grade, Access Control, Grade Separation, Vertical and Horizontal Alignment, Sight Distances, Interchange, Design, Operational, Clearance, Control, Right-of-Way
ENTIRE REPORT (Adobe Acrobat File – 1.6 MB)