IMPROVING EFFICIENCY OF INDOT TRAFFIC DATA COLLECTION USING GPS DEVICES

The Indiana Department of Transportation (INDOT) has utilized many new technologies to reduce travel delay, mitigate traffic congestion, and enhance public and employees' safety. Many projects are underway, including re-timing of most existing traffic signals and pavement maintenance and rehabilitation. To evaluate signal system performance, prioritize alternatives of improvement, conduct before and after studies and investigate work zone safety requires a large amount of traffic data such as travel time, speed and delay. Issues, such as safety, efficiency and cost, may arise associated with the current methods. The current manual or automatic data collection usually requires two operators, a driver and a recorder. The current methods also require much time for data processing and the resulting data files may not be reusable. With the global positioning system (GPS) technologies, it appears that traffic data collection can be performed more safely and efficiently. The objective of this study is to investigate use of the GPS technologies to improve efficiency of INDOT traffic data collection, to enhance field operation safety, and to reduce potential human errors. Primary emphasis is given to utilization of GPS receivers to acquire traffic data so as to generate a reusable data file. This kind of data file is essential for providing INDOT traffic engineers with consistent information for assessing the performance of signal systems. Secondary emphasis is given to use of the GPS data in specific transportation studies, such as travel time and delay studies, work zone studies, and congestion management. In this study, the GPS techniques were examined and the Trimble AgGPS 132 devices were tested using the precisely known geographic points. A computer program, GPS-Trek, was developed for data collection and data processing. A huge amount of data was collected over the selected routes. Based on the results of analysis and field tests, a summary of the major findings are as follows: The proposed GPS data collection system is inexpensive and cost-effective. It can improve the efficiency of traffic data collection, save manpower and enhance field operation safety. The AgGPS 132 receiver can provide traffic data of high accuracy and consistency. The field data may exhibit gaps in "deep" urban canyons. However, through interpolation and proper data screening these disadvantages may be limited. The removal of Selective Availability from the GPS signals further improves the accuracy of GPS data. It was shown that the relative positional accuracy using a DGPS service is well below the 0.5 m level. The GPS-Trek consists of two components, one for data collection and the other for data processing. The program is free of personal interpretation during data collection and provides a consistent system of analysis. The resulting data files are reusable. The data file can be easily exported to Microsoft Excel, allowing traffic engineers to utilize their own experience and judgment for data analysis and specific transportation studies.

  • Record URL:
  • Corporate Authors:

    Purdue University/Indiana Department of Transportation JHRP

    Purdue University, School of Civil Engineering
    West Lafayette, IN  United States  47907-1284

    Indiana Department of Transportation

    100 N Senate Avenue
    Indianapolis, IN  United States  46204

    Federal Highway Administration

    1200 New Jersey Avenue, SE
    Washington, DC  United States  20590
  • Authors:
    • Li, Shengbo Eben
    • Zhu, Karen
    • van Gelder, BHW
    • Nagle, J
    • Tuttle, C
  • Publication Date: 2002-6

Language

  • English

Media Info

  • Features: Figures; References; Tables;
  • Pagination: 92 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00960071
  • Record Type: Publication
  • Report/Paper Numbers: FHWA/IN/JTRP-2002/19,, Final Report
  • Contract Numbers: SPR-2392
  • Files: TRIS, ATRI, USDOT, STATEDOT
  • Created Date: Jul 11 2003 12:00AM