Abstract:
THE FUTURE DEVELOPMENT WAS PREDICTED FOR THE PRIMARY ROAD SYSTEM UP TO 1960 ON THE BASIS OF PAST PERFORMANCE AND INDICATED TRENDS. THE APPROACH IS ENTIRELY STATISTICAL, BASED UPON AN ANALYSIS OF CONSTRUCTION AND RETIREMENT MILEAGE DATA FROM 1917 TO 1938. SURVIVOR CURVES FOR THE VARIOUS SURFACE TYPES SHOW THE PERCENTAGE REMAINING IN SERVICE AT THE END OF EACH YEAR. FROM THESE CURVES THE PROBABLE MILEAGE TO BE RETIRED OF EACH SURFACE TYPE WAS OBTAINED FOR EACH YEAR DURING THE FORECAST PERIOD, 1940 TO 1960. FROM THE BASIC DATA FOR 1917 TO 1938, THE NEW TYPES CONSTRUCTED WHICH REPLACED TYPES RETIRED WERE OBTAINED AND TRENDS OF NEW CONSTRUCTION TYPES WERE ESTIMATED BY ESTABLISHING THE RELATION BETWEEN THE TYPE OF SURFACE CONSTRUCTED AND THE TYPE OF SURFACE REPLACED AT THE TIME OF RETIREMENT. THERE IS ALSO AN INCREASE IN THE PRIMARY STATE ROAD MILEAGE. THE PERCENTAGE OF INCREASE EACH YEAR WAS TABULATED, PLOTTED, AND A SMOOTH "CURVE OF AVERAGE PERCENT OF INCREASE" WAS FITTED TO THE PLOTTED DATA. ON THE BASIS OF PAST TRENDS THERE IS ON INDICATED INCREASE IN THE TOTAL PRIMARY STATE ROAD MILEAGE AFTER 1945. THE PROBABLY MILEAGE TO BE GRADED AND DRAINED EACH YEAR WAS LIKEWISE DETERMINED AND IT IS ESTIMATED THAT AN AVERAGE ANNUAL CONSTRUCTION OF 56 MILES OF GRADING AND DRAINAGE WILL BE INVOLVED WITH THE AVERAGE ANNUAL SURFACING PROGRAM OF 290 MILES. /AUTHOR/
Supplemental Notes:
Vol 21, pp 70-87, 11 FIG, 9 TAB. 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.
