TRUCK SPEEDS IN VIRGINIA: A STUDY TO EVALUATE THE ADEQUACY AND ADVISABILITY OF DIFFERENTIAL TRUCK-CAR SPEED LIMITS

RADAR SPEED CHECKS WERE CONDUCTED ON PRIMARY ROADS IN VIRGINIA AND ON PARTS OF THE INTERSTATE HIGHWAY SYSTEM ON OVER 10 THOUSAND VEHICLES DURING THE SPRING AND SUMMER OF 1966. A LITERATURE SEARCH WAS CONDUCTED ON THE RELATIONSHIP BETWEEN VEHICLE OPERATING COSTS AND TRAVEL SPEED. DATA WERE ANALYZED WITH THE CHI SQUARE TEST, THE T TEST, AND MULTIPLE REGRESSION ANALYSIS. SIX INDEPENDENT VARIABLES: GRADE, POSTED SPEED, NUMBER OF LANES, LANE WIDTH, AVERAGE DAILY TRAFFIC, AND NUMBER OF VEHICLES TESTED WERE RUN AGAINST THREE DEPENDENT MEASURES (85TH PERCENTILE, MEAN AND MODE) OF VEHICLE SPEED. THE MOST SIGNIFICANT FINDING OF THIS ANALYSIS WAS THAT NONE OF THE INDEPENDENT VARIABLES TAKEN SINGLY, NOR ALL OF THEM CUMULATIVELY, ADEQUATELY ACCOUNT FOR THE RESULTANT SPEED OF THE VEHICLE. IT WAS GENERALLY FOUND THAT NONE OF THE INDEPENDENT VARIABLES SERVED AS A SIGNIFICANT DETERMINANT OF OBSERVED SPEEDS. YET IT WAS ALSO FOUND THAT THE RELATIVE SIGNIFICANCE OF EACH VARIABLE AND THE RANKING OF THESE VARIABLES FOR EACH CLASS OF VEHICLES TESTED VARIED. IT IS CONCLUDED THAT THE CURRENT TRUCK SPEED LIMIT ON INTERSTATE HIGHWAYS IS UNREASONABLY LOW. SPEED DIFFERENTIALS EXIST ON THE PRIMARY SYSTEM BUT ARE NEITHER SO RECOGNIZABLE NOR CONSISTENT AS THOSE ON THE INTERSTATE SYSTEM. IT APPEARS THAT TRAFFIC IS DETERMINING ITS OWN MOST REASONABLE SPEED.

  • Supplemental Notes:
    • 40 Pp, Fig, TAB, REF, 11 APP
  • Corporate Authors:

    Virginia Highway Research Council

    Charlottesville, VA  USA 
  • Authors:
    • Ferguson, W S
  • Publication Date: 1968-1

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Filing Info

  • Accession Number: 00225390
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Oct 14 1994 12:00AM