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EVALUATION OF THE CAR ROAD METER BY USING THE K-COEFFICIENT

PRIOR TO DEVELOPMENT OF THE K-COEFFICIENT, COMPARISON OF RIDING COMFORT INDEX (RCI) VALUES WITH THOSE OF RATING PANELS ENTAILED TRANSFORMING THEM INTO LOGARITHMS. THE SAME WAS TRUE WHEN COMPARING RCI VALUES AT DIFFERENT SPEEDS FOR A GIVEN VEHICLE OR AMONG VEHICLES. IT WAS FOUND THAT THE RCI EQUATION COULD BE MODIFIED TO MULTIPLY THE COUNTER'S VALUE BY A FACTOR DETERMINED FROM THE LOCATION OF PAIRS OF SEGMENTS EQUIDISTANT ABOUT THE CENTER. THIS FACTOR IS A MULTIPLE OF 118 INCHES AND IS DIRECTLY PROPORTIONAL TO THE AMPLITUDES OF OSCILLATIONS. THE EQUATION THEN ASSUMES THE FORM RCI = K SIGMA DC, WHERE D IS EQUAL DISTANCE FROM THE CENTER, C IS THE READING ON THE COUNTER, AND THEIR PRODUCT IS THE MOMENT OF ANY SEGMENT. (NOTE: IN WHAT FOLLOWS, THE EXPRESSION "SIGMA DC" WILL BE REPRESENTED BY THE LETTER Q. - ABSTRACTER) HOWEVER, IF WE TAKE OUT THE SUM OF MOMENTS FROM THE PRECEDING EQUATION AND SET IT AGAINST A RESULTING MOMENT SUCH AS Q = M SIGMA C, WE CAN GET A RESULTING MOMENT ARM M WHOSE VALUE WILL BE M = Q/SIGMA C. THE EQUATION OF K- COEFFICIENT AS USED IN CALCULATION IS K = SIGMA C/Q; THEREFORE, THE K-COEFFICIENT IS THE RECIPROCAL OF THE RESULTING MOMENT ARM M. HOWEVER, THE K-COEFFICIENT HAS CERTAIN DRAWBACKS, SUCH AS FAILURE TO INDICATE THE DEGREE OF EXCELLENCE OF AN EXCELLENT PAVEMENT, INABILITY TO ACCOUNT FOR THE FREQUENCY OF BUMPS, AND INACCURATE REPRESENTATION OF INHOMOGENEOUS PAVEMENTS. THE THEORETICAL RESULTS WERE VERIFIED THROUGH TESTS WITH FOUR ROAD METERS. THE FOLLOWING CONCLUSIONS ARE REPORTED: (1) VERY GOOD LINEAR REGRESSIONS CAN BE OBTAINED FROM EACH VEHICLE AT DIFFERENT SPEEDS. THEREFORE, BY ADOPTING A SPECIFIC SPEED AS STANDARD, ALL VALUES OBTAINED AT OTHER SPEEDS CAN BE CONVERTED TO THOSE OBTAINED AT THE STANDARD ONE. (2) BY USING A GIVEN SPEED COMMON TO ALL VEHICLES, VALUES OF K CAN BE COMPARED AMONG VEHICLES. (3) ERRORS DURING CALIBRATION CAN BE EASILY DETECTED AND THE TYPE OF FAULT IDENTIFIED. (4) BY GIVING A VEHICLE'S OPERATOR THE RESULT OF CALIBRATIONS, HE CAN CHECK THE VEHICLE WHEN IN DOUBT OR PERFORM PERIODIC CALIBRATION RUNS WITH THE APPARATUS, ANYTIME AND ANYWHERE. THIS WILL PREVENT THE ACCUMULATION OF FALSE VALUES DURING INVENTORY OPERATIONS.

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  • Corporate Authors:

    Transportation Research Board

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  • Authors:
    • Fortin, Benjamin G
  • Conference:
  • Publication Date: 1973

Media Info

  • Media Type: Digital/other
  • Features: Figures; Tables;
  • Pagination: pp 97-102
  • Monograph Title: PAVEMENT EVALUATION USING ROAD METERS
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00207540
  • Record Type: Publication
  • Files: TRIS, TRB, ATRI
  • Created Date: May 21 1973 12:00AM