GEOGRAPHIC INFORMATION SYSTEMS/GLOBAL POSITIONING SYSTEMS DESIGN FOR NETWORK TRAVEL TIME STUDY

Abstract

In October 1993, Maricopa Association of Governments (MAG) conducted travel speed and delay studies in the metropolitan Phoenix area. This paper concentrates on a Geographic Information Systems (GIS)/data base systems approach to process the field data collected with Global Positioning Systems (GPS) units and portable computers after a brief discussion of the travel route selection and preparation and a brief comparison of the several different travel time survey techniques using the test vehicle method. The three system modules are described : the Field Data Conversion and Validation module uses the data base approach to combine the GPS data (position and speed) and event data into a data base format and uses ARC/INFO to check GPS run validity ; the Link Topology Definition module extracts topological information of the selected travel routes by data base programming and ARC/INFO's Dynamic Segmentation ; the Data Analysis and Reporting module structures the continuous GPS data on a link-by-link basis and calculates travel time, delay, and speed information for each link. This module also feeds the results to a SAS program for statistical analysis and to ARC/INFO for generating graphics reports. The system design is based on the interface between ARC/INFO 6.11 on the SUN Sparc Station and FoxPro 2.5 for DOS on PC.