25-10-2012, 11:41 AM
Interactive Graphics Intersection Design System (IGIDS) Enhancements
ABSTRACT
The Interactive Graphics Intersection Design System (IGIDS) is a computer software program developed for TxDOT that
assists engineers in the analysis and design of individual, at-grade intersections. IGIDS was initially developed under several
RMC 3 - Geometric Design, Environmental, Hydraulics, and Right-of-Way projects. IGIDS is a MicroStation application
which contains (1) geometric, traffic data, and signalization definition tools; (2) built-in analysis tools for vehicle turning
templates; horizontal sight distance checking for stop sign, yield sign, and no control; and ‘Highway Capacity Manual’
(HCM), Chapter 9 procedures; and (3) interfaces to external analysis programs for the TEXAS Model for Intersection Traffic
(TEXAS), the TxDOT Automated Plan Preparation System (APP), and the Signal Operations and Analysis Package (SOAP).
IGIDS can operate in English or metric units. IGIDS was recently enhanced by the addition of vertical sight distance checking
within the horizontal sight triangle, the inclusion of pavement striping definition and tabulation, and the development of
training materials. Most TxDOT engineers now use GEOPAK for the geometric design of intersections. TxDOT Traffic
Operations personnel generally have access to the GEOPAK design files for an intersection. IGIDS was enhanced to directly
read the intersection geometry from an existing GEOPAK design file. The addition of this feature makes IGIDS much easier
to use and reduce duplicated effort. In addition, most TxDOT engineers now prefer to use PASSER II-90 for signal timing
optimization rather than using SOAP. IGIDS was enhanced by the addition of a PASSER II-90 interface. The addition of this
feature increases the engineers’ ability to analyze and design an intersection for optimum operation. Since the last release of
IGIDS, the HCM Chapter 9 procedures have been updated. IGIDS was modified to use the 1998 version of the HCM Chapter
9 procedures. Training modules for these enhancements were developed and added to the training course previously developed
for IGIDS. In addition, each training module was updated to reflect recent experience using webbased training. Finally, a test
training session was held to evaluate the training materials and procedures.