EFFECTS OF TRAVEL IMPEDANCE COSTS

THE AUTHOR WAS INVOLVED IN SEVERAL TYPES OF TRAFFIC AND REVENUE STUDIES OVER THE YEARS. HE HAS DEVELOPED SEVERAL HYPOTHESES ON TRAFFIC DISTRIBUTION AND GENERATION. TWO SPECIFIC HYPOTHESES WERE SET FORTH IN 1945: ONE ON TRAFFIC DISTRIBUTION AND THE OTHER ON TRAFFIC GENERATION. THE TRAFFIC DISTRIBUTION HYPOTHESIS, EXPRESSED MATHEMATICALLY, STATED THAT EQUAL NUMERICAL DIFFERENCES IN IMPEDANCE COSTS BETWEEN A SELECTED AND ANY EXISTING ALTERNATE ROUTE ARE ASSOCIATED WITH EQUAL PERCENTAGE DIFFERENCES IN THE OPPOSITE DIRECTION AND IN THE QUALITY RATINGS OF THE EXISTING ROUTES. THE TRAFFIC GENERATION HYPOTHESIS, EXPRESSED MATHEMATICALLY, STATED THAT THE DIFFERENCE IN TRIPS BETWEEN ANY PAIR OF ZONES (ONE A RESIDENCE AND THE OTHER A NON-RESIDENCE ZONE) AND A STANDARD PAIR OF CORRESPONDING ZONES, ARE: (1) PROPORTIONAL TO THE DIFFERENCES IN THE AUTO REGISTRATION IN THE TWO RESIDENCE ZONES, (2) PROPORTIONAL TO THE DIFFERENCES IN THE INDEXES OF ATTRACTION IN THE NON-RESIDENCE OR PURPOSE ZONES, AND (3) INVERSELY PROPORTIONAL TO A FUNCTION OF THE DIFFERENCES IN IMPEDANCE COSTS BETWEEN THE GIVEN PAIR OF RESIDENCE AND NON-RESIDENCE ZONES AND THE CORRESPONDING STANDARD ZONES. THESE FORMULAS ARE PRESENTED AND MR. G.P.ST. CLAIR PUT THESE TWO HYPOTHESES AND THEIR CORRESPONDING SERIES OF EQUATIONS THROUGH THOROUGH AND RIGOROUS MATHEMATICAL TESTS. HE SUGGESTED AN ALTERNATE HYPOTHESIS IN CONNECTION WITH THE AUTHOR'S TRAFFIC DISTRIBUTION HYPOTHESIS THAT MIGHT BRIEFLY BE STATED THAT: ALL ALTERNATE ROUTES HAVE EQUAL IMPEDANCE COSTS. IN ADDITION, HE DERIVED FROM THE AUTHOR'S EXPONENTIAL FUNCTIONS, BY THE METHOD OF CALCULUS, EXPONENTIAL-TYPE-SKEWED FUNCTION AND NORMAL-TYPE-SKEWED FUNCTION. THEY APPEAR TO BE REALISTIC REFLECTIONS OF BOTH TRAFFIC GENERATION AND THE TYPES OF LINKAGES THAT APPEAR TO EXIST BETWEEN HOMES AND SITES OF ECONOMIC ACTIVITY. THESE FUNCTIONS WOULD YIELD MEASURES FOR A NUMBER OF HIGHLY INTERESTING CHARACTERISTICS OF TRIP LINKAGES BETWEEN SITES OF CONCENTRATED ECONOMIC ACTIVITY AND SURROUNDING RESIDENCE AREAS. THEY WOULD REVEAL RELATIONSHIPS BETWEEN INCREASING TRAVEL IMPEDANCE COSTS AND DECREASING RENTALS IN RESIDENTIAL AREAS LOCATED AT VARIOUS TRAVEL IMPEDANCE COSTS FROM CONCENTRATED ECONOMIC AREAS, LIKE CBD'S. THE SO-CALLED GRAVITY FORMULA WHICH STATES THAT TRIPS VARY INVERSELY AS SOME POWER OF DISTANCE OR TIME, DOES NOT APPEAR TO BE THE MATHEMATICAL FUNCTION BEST SUITED TO EXPRESS THE INVERSE RELATIONSHIP BETWEEN TRIPS AND IMPEDANCE COSTS. SERIOUS CONSIDERATION SHOULD BE GIVEN TO ASSEMBLE ORIGIN-DESTINATION DATA ON SITES AND AREAS OF ECONOMIC, SOCIAL AND RECREATIONAL ACTIVITIES IN URBAN AREAS.

Media Info

  • Monograph Title: ECONOMIC ANALYSIS IN HIGHWAY PROGRAMMING, LOCATION AND DESIGN: WORKSHOP CONFERENCE PROCEEDINGS, SEPTEMBER 17, 1959
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00201829
  • Record Type: Publication
  • Files: TRIS, TRB
  • Created Date: Aug 26 1970 12:00AM