ESTIMATION OF SPEED FROM PRESENCE DETECTORS

PRESENCE DETECTORS ARE CURRENTLY IN USE IN SURVEILLANCE AND RAMP CONTROL PROJECTS IN SEVERAL CITIES IN THE UNITED STATES. THE DATA OBTAINED FROM THOSE DETECTORS ARE USUALLY PROCESSED TO PRODUCE TRAFFIC VOLUMES AND OCCUPANCIES. BY MAKING CERTAIN ASSUMPTIONS, IT IS POSSIBLE TO OBTAIN ESTIMATES OF THE AVERAGE (SPACE MEAN) SPEED OF A GROUP OF VEHICLES PASSING OVER A SINGLE SENSOR. THE SIMPLEST ESTIMATORS (OF THE FORM LENGTH DIVIDED BY DETECTOR ON TIME) ARE BASED. THE PURPOSE OF THIS PAPER IS TO DEVELOP UNBIASED, MINIMUM MEAN SQUARE ERROR ESTIMATES OF SPEED. THESE NEW SPEED ESTIMATORS DIFFER FROM THE SIMPLEST ESTIMATORS IN THAT ON-TIME ASSOCIATED WITH THE PASSAGE OF INDIVIDUAL VEHICLES ARE PROCESSED SEPARATELY. ALTHOUGH INDIVIDUAL SPEEDS CANNOT BE DETERMINED VERY ACCURATELY, THE ESTIMATORS DEVELOPED HERE ARE CAPABLE OF DETERMINING THE AVERAGE (SPACE MEAN) SPEED OF, SAY, 20 VEHICLES TO WITHIN 4 MPH. A FREEWAY TRAFFIC SIMULATION IS EMPLOYED TO ILLUSTRATE THE SUPERIORITY OF THE ESTIMATORS DERIVED HERE. /AUTHOR/

Media Info

  • Media Type: Print
  • Features: Appendices; Figures; References; Tables;
  • Pagination: pp 73-83
  • Monograph Title: Freeway operations and control
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00226401
  • Record Type: Publication
  • Report/Paper Numbers: No 390 PP 36-9
  • Files: TRIS, TRB
  • Created Date: Sep 19 1972 12:00AM