USERS MANUAL FOR THE HIGHWAY GEOMETRIC DESIGN CONSISTENCY PROGRAM (ENGLISH UNITS)

The Highway Geometric Design Consistency (HGDC) program is a menu-driven microcomputer-based procedure for evaluating the geometric design consistency of rural two-lane highways in level or rolling terrain. The program estimates two measures of horizontal alignment design consistency: the decrease in 85th percentile operating speed, and the increase in driver workload, from an approach tangent to a horizontal curve. These consistency measures are estimated based on models developed under the subject contract and documented in Publication No. FHWA-RD-94-034 (TRIS 00674248), entitled Horizontal Alignment Design Consistency for Rural Two-Lane Highways (Jan. 1995). This report is the users manual for the metric-units version of the HGDC program. (There is a separate English-units version of the program.) This manual describes the capabilities and input data requirements of the program. It also describes the mechanics of using this menu-driven program, including the meaning of each option on the program menus.