TRENDS IN THE 30TH-HOUR FACTOR

AN ANALYSIS OF AUTOMATIC TRAFFIC RECORDER DATA FOR RURAL HIGHWAYS REVEALS THAT THE 30TH-HOUR FACTOR EXHIBITS A TENDENCY TO DECLINE SLIGHTLY WITH THE PASSING OF TIME, RATHER THAN TO REMAIN STABLE AS PAST INDICATIONS HAVE SUGGESTED. RECORDS FOR 160 TRAFFIC-RECORDER STATIONS IN CONTINUOUS OPERATION FROM 1946 THROUGH 1953 PROVIDED THE ANALYSIS. ALL CLASSES OF RURAL HIGHWAYS WERE REPRESENTED AND THE COVERAGE INCLUDED 26 STATES. THE AVERAGE FACTOR FOR THESE STATIONS DECLINED AT THE AVERAGE RATE OF 0.11 PER YEAR OVER THE 7-YR PERIOD BUT A WIDE VARIATION IN THE RATE OF DECLINE WAS FOUND BETWEEN DIFFERENT STATIONS. ROADS WITH VOLUMES OF MORE THAN 3,000 VEHICLES ADT EXPERIENCED A MORE RAPID RATE OF DECLINE IN THE FACTOR THAN THE ROADS WITH LESSER VOLUMES. ALSO, FACTORS OF 15, OR GREATER, EXPERIENCED A MORE RAPID RATE OF DECLINE THAN FACTORS OF LESS THAN 15. A TABLE WHICH RELATES THE ANNUAL CHANGE IN THE FACTOR TO BOTH THE MAGNITUDE OF THE FACTOR AND THE ADT IS INCLUDED IN THE REPORT. /AUTHOR/

• Record URL:
  http://onlinepubs.trb.org/Onlinepubs/hrbbulletin/167/167-006.pdf
• Supplemental Notes:
  • No 167, pp 75-83, 4 FIG, 1 TAB, 2 REF, 1 APP 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:
  • Walker, William P
• Publication Date: 1957

Media Info

• Monograph Title: Highway capacity studies
• Serial:
  • Highway Research Board Bulletin
  • Issue Number: 167
  • Publisher: Highway Research Board

Subject/Index Terms

• TRT Terms: Average daily traffic; Design hourly volume; Recording; Rural highways; Traffic counting; Traffic counting stations; Traffic volume
• Old TRIS Terms: Thirtieth highest annual hourly volume
• Subject Areas: Highways; Operations and Traffic Management;

Filing Info

• Accession Number: 00225406
• Record Type: Publication
• Files: TRIS, TRB
• Created Date: Apr 28 1994 12:00AM