THE OPTIMAL SPACING OF ARTERIALS AND EXPRESSWAYS

AN INVESTIGATION WAS MADE INTO THE OPTIMAL SPACING OF EXPRESSWAYS AS A FUNCTION OF COSTS OF MOVEMENT AND COSTS OF CONSTRUCTION. A DISTANCE FREQUENCY DISTRIBUTION WAS ASSUMED. THE TWO VARIABLES CONSIDERED WERE CONSTRUCTION COSTS AND COST OF TRAVEL. THE SOLUTION WAS MATHEMATICALLY DEVELOPED USING A SET OF INTEGRALS AND A SET OF SUMMATIONS. THE FOLLOWING CONCLUSIONS WERE REACHED' /1/ THE OPTIMUM SPACING OF ARTERIALS AND EXPRESSWAYS INCREASES AS THE COST PER MILE INCREASES. /2/ OPTIMUM SPACING OF EXPRESSWAYS AND ARTERIALS DECREASE AS THE TRAFFIC DENSITY INCREASES AND AS THE TIME PERIOD OVER WHICH OPERATING COSTS ARE FIGURED INCREASES. /3/ IF THE RELATIVE SPEED OF EXPRESSWAYS INCREASES IN RELATIONSHIP TO THAT OF ARTERIALS AND LOCAL STREETS THEN THE OPTIMUM SPACING DECREASES. /4/ IF THE VALUE OF HIGH SPEED TRAFFIC INCREASES, THEN THE OPTIMUM SPACING OF EXPRESSWAYS DECREASES. /5/ IF THE DISTRIBUTION OF TRIPS SHIFTS TOWARD LONGER TRIPS, OPTIMUM EXPRESSWAY SPACING DECREASES. /6/ IF EXPRESSWAYS ARE MUCH MORE EXPENSIVE THAN ARTERIALS, THEY WILL BE RELATIVELY FARTHER APART THAN ARTERIALS-BUT ONLY AS THE SQUARE ROOT OF THE RELATIONSHIP. /7/ IF ARTERIAL SPEEDS BECOME FASTER THAN THOSE OF LOCAL STREETS, EXPRESSWAYS BECOME FARTHER APART AND /8/ IF EXPRESSWAY SPEEDS INCREASE OVER THOSE OF ARTERIALS, EXPRESSWAYS BECOME CLOSER TOGETHER.

  • Supplemental Notes:
    • Research NeWS, PP 10-16, 2 TAB
  • Corporate Authors:

    Chicago Area Transportation Study

    300 West Adams Street
    Chicago, IL  United States  60606
  • Authors:
    • Creighton, R L
    • Schneider, M
  • Publication Date: 1958-11

Subject/Index Terms

Filing Info

  • Accession Number: 00240884
  • Record Type: Publication
  • Source Agency: Urban Transp Plng Abstracts /Prelim
  • Files: TRIS
  • Created Date: Aug 5 1994 12:00AM