A STUDY OF THE ACCURACY AND RELIABILITY OF AUTOMATIC TRAFFIC RECORDING DEVICES. FINAL REPORT

The Automatic Traffic Recorder (ATR) counts the vehicular traffic which passes over a set of sensors that are fixed in position on a given roadway. The modern ATR not only counts the vehicles, but determines which of 14 classes (defined by FHWA Scheme F) the vehicle fits into, measures the vehicle speed, and provides separate totals for each class and for each speed range. The objective of this program was to design and build a device which emits patterns of simulated roadway sensor outputs (signatures) to test the accuracy of the counting and classification functions of the modern ATR. In an actual installation, the types and spacing and arrangement of the roadway sensors are variables. The tester accommodates these variables, as well as providing a great deal of flexibility in the overall test duration, counting intervals (time), number of lanes counted simultaneously, and format of the data cabling between components. The test setup is eased considerably by the extensive use of sequenced menu selections, which ask the appropriate questions, and list the possible responses. After the tester setup is complete, the operator is prompted to setup the ATR in a compatible fashion. The cabling is then connected, and the tester begins to transmit a variety of signatures to the ATR at various speeds, based on the setup information. The tester software records the count, class, and speed of each signature output to the ATR for the specified test duration, and then automatically records the output report to disk. After retrieving the observed count, class, and speed information from the ATR, the two reports are compared to determine the accuracy of the ATR. The result is a device which has been verified to provide appropriate vehicle signatures to a variety of makes and models of ATR. The device has been used to test about 150 individual units of a single model of ATR (StreeterAmet 241), and gave consistent results. Over time the use of this tester will add to the credibility of the data used in usage studies, save time and money by reducing the errors and defective data collection, and help pinpoint the weak areas in the ATRs used by the State of Ohio.

• Corporate Authors:

  Athens Technical Specialists, Incorporated

  20 East Circle Drive, Suite 190
  Athens, OH  United States  45701

  Ohio Department of Transportation

  25 South Front Street
  Columbus, OH  United States  43215

  Federal Highway Administration

  1200 New Jersey Avenue, SE
  Washington, DC  United States  20590
• Authors:
  • Gilfert, J C
• Publication Date: 1996-1

Language

• English

Media Info

• Features: Appendices; Figures; Photos; References; Tables;
• Pagination: 56 p.

Subject/Index Terms

• TRT Terms: Accuracy; Reliability; Software; Testing equipment; Traffic counts
• Subject Areas: Highways; Operations and Traffic Management; Planning and Forecasting; I72: Traffic and Transport Planning;

Filing Info

• Accession Number: 00720117
• Record Type: Publication
• Report/Paper Numbers: FHWA/OH-95/022
• Contract Numbers: State Job No. 14529(0)
• Files: TRIS, USDOT, STATEDOT
• Created Date: Apr 10 1996 12:00AM