ROAD SURFACE TEXTURE AND THE CHANGE IN SKIDDING RESISTANCE WITH SPEED

PAST WORK HAS INDICATED THAT ON WET ROADS THE RATE OF DECREASE OF SKIDDING RESISTANCE WITH SPEED IS LARGELY DEPENDENT ON THE COARSENESS OF THE ROAD SURFACE TEXTURE. ON SMOOTH, FINE-GRAINED SURFACES THE COEFFICIENT DECREASES RAPIDLY WITH SPEED, BUT ON COARSE-TEXTURED SURFACES THE DECREASE IS MUCH LESS RAPID. TESTS HAVE NOW BEEN CARRIED OUT TO EXAMINE MORE CLOSELY THE WAY IN WHICH COEFFICIENTS DECREASE WITH SPEED UP TO 80 MILE/H AND TO ATTEMPT TO FIND A QUANTITATIVE MEASURE OF SURFACE TEXTURE WHICH WILL INDICATE THE RATE OF FALL IN COEFFICIENT WITH SPEED. TWO TECHNIQUES OF MEASURING TEXTURE HAVE BEEN EXAMINED: THE 'SAND-PATCH' METHOD FROM WHICH A MEASURE OF 'TEXTURE DEPTH' CAN BE OBTAINED, AND A NEW STEREOPHOTOGRAMMETRIC TECHNIQUE WHICH RECORDS THE SURFACE PROFILE. A STATISTICAL CORRELATION HAS BEEN OBTAINED BETWEEN THE PERCENTAGE DECREASE IN COEFFICIENT BETWEEN 30 AND 80 MILE/H AND THE TEXTURE DEPTH, WHICH MEASURES THE COARSENESS OF TEXTURE. RECOMMENDATIONS FOR TEXTURE-DEPTH REQUIREMENTS FOR FAST ROADS ARE GIVEN: TO RESTRICT THE DECREASE TO LESS THAN ABOUT 25 PER CENT, A TEXTURE DEPTH OF MORE THAN 0.025 IN APPEARS NECESSARY. A BETTER CORRELATION WITH PERCENTAGE DECREASE IN COEFFICIENT IS OBTAINED BY A MEASURE OF THE SURFACE PROFILE (THE 'PROFILE RATIO') WHICH TAKES INTO ACCOUNT THE SHAPE OF PROJECTIONS IN THE SURFACE. /AUTHOR/

  • Supplemental Notes:
    • Report No 20, 19 PP, 9 FIG, 3 TAB, 4 REF
  • Corporate Authors:

    Road Research Laboratory /UK

    ,    
  • Authors:
    • SABEY, B E
  • Publication Date: 1966

Subject/Index Terms

Filing Info

  • Accession Number: 00203457
  • Record Type: Publication
  • Source Agency: Nat Safety Council Safety Res Info Serv
  • Files: TRIS, ATRI
  • Created Date: Jun 22 1970 12:00AM