A METHODOLOGY TO RELATE TRAFFIC ACCIDENTS TO HIGHWAY DESIGN CHARACTERISTICS

IN THE FIRST PHASE OF THE STUDY THE ACCIDENT RATE PER MILLION VEHICLE-MILES IS RELATED TO INDIVIDUAL HIGHWAY DESIGN CHARACTERISTICS SUCH AS, CURVATURE, GRADIENT, PAVEMENT WIDTH AND SHOULDER WIDTH. THE RESULTS ARE AS FOLLOWS: (1) THE CURVATURE IS OFTEN CHARACTERIZED AS A HAZARDOUS ROAD VARIABLE. A SCATTER PLOT OF DATA POINTS INDICATED THAT THE ACCIDENT RATE INCREASED WITH DEGREE OF CURVATURE, (2) THE SCATTER PLOT OF ACCIDENT RATE AGAINST PER CENT OF GRADIENT DID NOT SHOW AS STRONG A RELATIONSHIP AS IN CURVATURE BUT A GENERAL INCREASE IN THE ACCIDENT RATE WITH THE PER CENT OF GRADIENT IS EVIDENT, (3) PAVEMENT WIDTH DATA SHOWED A DEFINITE RELATIONSHIP WITH THE ACCIDENT RATE. PAVEMENTS 22 TO 24 FEET WIDE WERE SAFER THAN NARROW PAVEMENTS AND WIDER PAVEMENTS, AND (4) WIDER SHOULDERS APPEARED TO RESULT IN FEWER ACCIDENTS, BUT THE RELATIONSHIP WAS NOT VERY CLEAR. IN THE SECOND PHASE, REGRESSION ANALYSIS WERE MADE TO RELATE THE ACCIDENT RATE PER MILLION VEHICLES PASSING A POINT TO THE INDIVIDUAL AND COMBINATIONS OF THE HIGHWAY DESIGN CHARACTERISTICS. THE RESULTS WERE AS FOLLOWS: (1) CURVATURE, GRADIENT, PAVEMENT WIDTH AND SHOULDER WIDTH WERE SIGNIFICANT CONTRIBUTORS TO THE ACCIDENT EXPERIENCE BUT NO SINGLE VARIABLE ACCOUNTED FOR ALL VARIATIONS IN ACCIDENT RATES, (2) THE INTERACTIONS OF THE CURVATURE WITH GRADE, AND PAVEMENT WIDTH WITH GRADE ARE SIGNIFICANT CONTRIBUTORS TO ACCIDENT RATES, (3) A USEFUL REGRESSION EQUATION WHICH INCLUDED CURVATURE, GRADE AND PAVEMENT WIDTH IS DEVELOPED BY A NON-LINEAR MULTIPLE REGRESSION TECHNIQUES, AND (4) IT IS SUGGESTED THAT FURTHER, SIMILAR STUDIES, USING MORE DATA AND INCLUDING OTHER IMPORTANT VARIABLES MAY PROVIDE EFFECTIVE INFORMATION ON CRITICAL FACTORS IN HIGHWAY SAFETY. /SRIS/

• Supplemental Notes:
  • 78 Pp, 7 FiG, 19 TAB, 12 REF
• Corporate Authors:

  Ohio University, Athens

  Department of Industrial and Manufacturing Systems Engineering
  Athens, OH  United States  45701
• Authors:
  • Shah, K
• Publication Date: 1968-8-31

Subject/Index Terms

• TRT Terms: Crash rates; Curvature; Graphics; Hazards; Highway design; Highway grades; Methodology; Pavements; Regression analysis; Road shoulders; Slopes; Traffic crashes; Vehicles; Width
• Uncontrolled Terms: Graphical analysis; Horizontal curvature; Interaction
• Old TRIS Terms: Pavement width
• Subject Areas: Data and Information Technology; Design; Highways; Operations and Traffic Management; Pavements; Safety and Human Factors; Vehicles and Equipment;

Filing Info

• Accession Number: 00225841
• Record Type: Publication
• Source Agency: Nat Safety Council Safety Res Info Serv
• Files: TRIS
• Created Date: Oct 5 1970 12:00AM