DEVELOPMENT OF TRAFFIC PARAMETER FOR STRUCTURAL DESIGN OF FLEXIBLE PAVEMENTS IN MINNESOTA

DURING THE LAST 5 YEARS A COMPREHENSIVE STUDY WAS MADE OF FLEXIBLE PAVEMENT DESIGN AND PERFORMANCE IN MINNESOTA. THIS STUDY WAS BASED ON MEASUREMENTS AND OBSERVATIONS ON 50 TEST SECTIONS, ALL ON EXISTING STATE HIGHWAYS. A TRAFFIC STUDY WAS USED TO OBTAIN TRAFFIC DISTRIBUTIONS PLUS TOTAL VOLUME OF TRAFFIC TO USE THE ROADWAY AT EACH TEST SECTION. THE LOAD EQUIVALENCIES OBTAINED AT THE AASHO ROAD TEST ARE USED TO CONVERT MIXED TRAFFIC TO A NUMBER OF EQUIVALENT 18,000-POUND AXLE LOADS. THE DISTRIBUTION AND VOLUMES OBTAINED IN THE TRAFFIC STUDY ARE USED TO: (1) CALCULATE THE TOTAL EQUIVALENT 18,000-POUND AXLE LOADS THAT THE SECTION HAS BEEN SUBJECTED TO SINCE IT WAS LAST RESURFACED, AND (2) DETERMINE WHAT TRAFFIC PARAMETERS BEST PREDICT THE TOTAL EQUIVALENT LOADS ON A PAVEMENT SECTION AND HOW ACCURATELY THESE PARAMETERS PREDICT THE EQUIVALENT AXLE LOADS. A PROCEDURE WAS DEVELOPED FOR DETERMINING ON A COMPUTER THE TOTAL EQUIVALENT 18,000-POUND AXLE LOADS ON EACH TEST SECTION. THE EQUIVALENT 18,000-POUND AXLE LOADS CAN BEST BE PREDICTED FROM THE DAILY SUM OF TYPE 4 PLUS TYPE 5 TRUCKS ON A SECTION OF ROAD. CORRELATIONS WERE MADE BETWEEN THE EQUIVALENT AXLE LOADS AND: (1) AVERAGE DAILY TRAFFIC (ADT), (2) THE HEAVY COMMERICAL AVERAGE DAILY TRAFFIC (HCADT), AND (3) THE SUMMATION OF TYPE 4 PLUS TYPE 5 TRUCKS. IT IS SHOWN THAT THE EQUIVALENT LOADS CAN BE PREDICTED WITH INCREASING ACCURACY USING THE FIRST THREE PARAMETERS IN ORDER AS LISTED. THE ERRORS IN THESE PREDICTIONS ARE RELATED TO DESIGN THICKNESS. THE EQUIVALENT 18,000-POUND AXLE LOADS CAN BEST BE PREDICTED FROM THE DAILY SUM OF TYPE 4 PLUS TYPE 5 TRUCKS ON A SECTION OF ROAD. HOWEVER, THE PREDICTION USING THE HCADT IS ONLY SLIGHTLY WORSE AND IS RECOMMENDED FOR DESIGNING FLEXIBLE PAVEMENTS. FOR THE PRESENT MINNESOTA DEPARTMENT OF HIGHWAYS DESIGNED PROCEDURE, THE 2-WAY HCADT IS USED AS THE DESIGN PARAMETER. IT IS RECOMMENDED THAT THE HCADT CONTINUE TO BE USED FOR TRAFFIC DETERMINATIONS AND THAT AN INCREASE OF 5% IN LOG N18 IN THE EQUATION RELATIVE TO HCADT BE USED AND AN INCREASE OF 3% IN HCADT BE USED FOR DESIGN PURPOSES IF NO OTHER PARTICULARS ARE KNOWN ABOUT THE DESIGN TRAFFIC. IT IS THUS RECOMMENDED THAT AN ANNUAL GROWTH FACTOR OF 8% IN LOG N18 BE USED FOR DESIGN PURPOSES.

• Record URL:
  http://onlinepubs.trb.org/Onlinepubs/hrr/1969/291/291-008.pdf
• Supplemental Notes:
  • Paper sponsored by Committee on Flexible Pavement Design and presented at the 48th Annual Meeting.Distribution, posting, or copying of this PDF is strictly prohibited without written permission of the Transportation Research Board of the National Academy of Sciences. Unless otherwise indicated, all materials in this PDF are copyrighted by the National Academy of Sciences. Copyright © National Academy of Sciences. All rights reserved
• Authors:
  • Skok Jr, Eugene L
• Publication Date: 1969

Media Info

• Media Type: Print
• Features: Figures; References; Tables;
• Pagination: pp 104-115
• Monograph Title: Design, evaluation, and performance of pavement systems
• Serial:
  • Highway Research Record
  • Issue Number: 291
  • Publisher: Highway Research Board

Subject/Index Terms

• TRT Terms: Average daily traffic; Axle load force; Commercial vehicles; Flexible pavements; Pavement design; Pavement performance; Structural design; Test sections; Traffic surveys; Traffic volume
• Uncontrolled Terms: Traffic studies
• Geographic Terms: Minnesota
• Subject Areas: Highways; Pavements;

Filing Info

• Accession Number: 00205777
• Record Type: Publication
• Files: TRIS, TRB
• Created Date: Mar 9 1970 12:00AM