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https://nap.nationalacademies.org/catalog/27432/critical-issues-in-transportation-for-2024-and-beyond

TOWARD THE DERIVATION OF SIMULTANEOUS EQUATION MODELS FOR ESTIMATING WINTER MAINTENANCE COSTS IN PENNSYLVANIA

DUNLAY'S THEORETICAL MODEL IS COMPOSED OF TWO SYSTEMS OF SIMULTANEOUS EQUATIONS. HIS CALIBRATED MODEL, HOWEVER, SHOWED UNUSUALLY HIGH "STUDENT T" RATIO THE ESTIMATED PARAMETERS. THIS PROMPTED US TO RE-EXAMINE HIS 1968-69 MODEL. THE EXAMINATION UNCOVERED A MISTAKE IN THE COMPUTATION MANUAL WHICH PRODUCED A SET OF MUTUALLY EXCLUSIVE MULTIPLE REGRESSIONS RATHER THAN A SYSTEM OF INTERDEPENDENT EQUATIONS. THEREFORE DUNLAY'S THEORETICAL MODEL WAS RECALIBRATED AND SEVERAL ALTERNATIVE STRUCTURES WERE ALSO CALIBRATED, USING 1968-69 AND 1969-70 WINTER SEASON DATA. THE CONSISTENCY TESTS AND THE VALIDATION DISCUSSIONS ARE CONFINED TO THE PARAMETERS OF THE RECALIBRATED DUNLAY'S QUADRATIC FORM MODEL, BUT NO VALIDATION, DISCUSSIONS ARE PRESENTED FOR THE SEVERAL ALTERNATIVE STRUCTURES BECAUSE THEY ARE REDUNDANT OF THE FORMER VALIDATION. THE VALIDATION TESTS SHOW THAT INCONSISTENCIES EXIST IN THE VALUE OF THE ESTIMATED PARAMETERS FOR THE TWO WINTER PERIODS. THESE INCONSISTENCIES COULD BE ATTRIBUTED PARTIALLY TO AUSTERITY POLICIES IN EFFECT DURING THE WINTER OF 1969-70 AND PARTIALLY TO EX REME DIFFERENCES IN THE SEVERITY OF THE TWO WINTERS. THE 1968-69 AND 1970-71 DATA ARE RECOMMENDED AS APPROPRIATE DATA FOR DEVELOPING AND CALIBRATING WINTER MAINTENANCE MODELS FOR PENNSYLVANIA. THE PERIUODS REPRESENT A MILD AND A SEVERE WINTER RESPECTIVELY, WITH NO AUSTERITY POLICY CONSTRAINTS.

  • Supplemental Notes:
    • Contract 40755
  • Corporate Authors:

    Pennsylvania Transportation and Traffic Safety Center

    ,    
  • Authors:
    • Spottheim, D
  • Publication Date: 0

Subject/Index Terms

Filing Info

  • Accession Number: 00218095
  • Record Type: Publication
  • Source Agency: Federal Highway Administration
  • Files: TRIS, USDOT
  • Created Date: May 15 1974 12:00AM