TRAFFIC COUNT CAPABILITIES OF FISCHER AND PORTER TAC-DET LOOP DETECTORS AND CARD KEY SYSTEMS TRANS-SENSOR DETECTORS

THIS STUDY COMPARES THE OPERATIONAL CHARACTERISTICS, PRECISION, INSTALLATION PROBLEMS AND COSTS OF THE TAC-DET LOOP VEHICLE DETECTOR AND CARD KEY SYSTEMS TRANS-SENSOR DETECTOR AT AN EIGHT LANE FREEWAY LOCATION. THE TRANS-SENSOR IS A MAGNETIC TYPE VEHICLE DETECTOR WHICH HAS GIVEN QUITE SATISFACTORY PERFORMANCE IN BOTH LABORATORY AND FIELD TESTS. THE FIELD EVALUATION CONSISTED OF COMPARING THE TRANS-SENSOR DETECTOR COUNTS WITH DIRECT ON-SITE OBSERVATIONS AND WITH AN ADJACENT INSTALLATION OF THE WIDELY USED FISCHER & PORTER TAC-DET LOOP DETECTOR. TRANS-SENSOR PERFORMANCE IN THESE TESTS WAS SOMEWHAT BETTER THAN THAT OF TAC-DET. TWO OF THE FACTORS RESPONSIBLE FOR THE TRANS-SENSORS SUPERIOR PERFORMANCE ARE AS FOLLOWS' /1/ THE TRANS-SENSORS GREATER LATERAL SPACING BETWEEN DETECTOR UNITS IN ADJACENT LANES PRODUCED FEWER DOUBLE COUNTS FROM LANE CHANGING VEHICLES, AND /2/ THE TRANS-SENSOR WAS EQUIPPED WITH AN ADJUSTABLE TIME HOLDING CIRCUIT THAT PREVENTS THE RELAY CONTACTS FROM BREAKING BETWEEN A TRACTOR AND TRAILER OF A TRUCK RIG. THE TRANS-SENSOR THUS PRODUCED FEWER MULTIPLE COUNTS OF COMBINATION VEHICLES. INSTALLATION PROCEDURES FOR THE TWO DETECTORS ARE DESCRIBED AND COMPARED ON A TIME BASIS. THIS TIME COMPARISON IS THEN PROJECTED TO A COST COMPARISON PER STATION FOR CONCRETE AND ASPHALT PAVEMENT. /BPR/

• Supplemental Notes:
  • Hpr-1/4/, C-1-2 /STATE/
• Corporate Authors:

  California Division of Highways

  Bridge Department
  Sacramento, CA  United States  05914
• Authors:
  • Wasser, C F
• Publication Date: 1966-9-14

Subject/Index Terms

• TRT Terms: Alternatives analysis; Asphalt pavements; Concrete pavements; Costs; Electromagnetic fields; Evaluation; Field tests; Freeways; Installation; Traffic counting; Vehicle detectors
• Old TRIS Terms: Card key systems; Fischer & porter; Tac-det loop detector; Trans-sensor detector
• Subject Areas: Finance; Highways; Maintenance and Preservation; Safety and Human Factors;

Filing Info

• Accession Number: 00219665
• Record Type: Publication
• Source Agency: Bureau of Public Roads /US
• Files: TRIS
• Created Date: Oct 1 1994 12:00AM