ESTIMATION OF COUNTY PRIMARY ROAD SYSTEM NEEDS BY SAMPLE SURVEY METHODS

HIGHWAY NEEDS STUDIES ARE COSTLY AND TIME CONSUMING AND REQUIRE LARGE ENGINEERING STAFFS FOR THEIR PERFORMANCE. THIS STUDY IS AN INVESTIGATION OF WHETHER SAMPLE SURVEY METHODS CAN BE USED TO REDUCE THE TIME AND WORK REQUIRED TO MAKE STUDIES. COMPLETE INVENTORY AND COST DATA WERE AVAILABLE FOR THE PRIMARY COUNTY ROAD SYSTEMS IN MICHIGAN AND MINNESOTA AND THIS INFORMATION WAS USED FOR STATISTICAL ANALYSIS. THE VALUE OF POPULATION CHARACTERISTICS AND THE VARIANCES OF THESE CHARACTERISTICS WERE COMPUTED FOR THE COMPLETE DATA OF EACH STATE.FOUR DIFFERENT SAMPLING METHODS WERE INVESTIGATED FOR REQUIRED SAMPLE SIZE USING FIVE DIFFERENT COMBINATIONS OF MARGIN OF ERROR AND A RISK FOR EACH POPULATION. THE METHODS INVESTIGATED WERE: (1) SIMPLE RANDOM SAMPLING,(2) STRATIFIED RANDOM SAMPLING WITH OPTIMUM AND PROPORTIONAL ALLOCATION, (3) SIMPLE CLUSTER SAMPLING, AND (4) STRATIFIED CLUSTER SAMPLING WITH OPTIMUM AND PROPORTIONAL ALLOCATION. USING THE FIVE COMBINATIONS OF MARGIN OF ERROR AND A RISK FOR EACH POPULATION, SAMPLE SIZES REQUIRED FOR THE ESTIMATE OF TOTAL COST OF STATEWIDE NEEDS WERE COMPUTED. SAMPLE SIZES REQUIRED FOR THE ESTIMATION OF OTHER POPULATION TOTALS WERE ALSO COMPUTED. FOR A GIVEN MARGIN OF ERROR AND A RISK FOR EACH POPULATION ALL FORMS OF CLUSTER SAMPLING USED REQUIRED SUBSTANTIALLY LARGER SAMPLING RATES FOR THE ESTIMATE OF TOTAL COST THAN THOSE REQUIRED FOR SIMPLE RANDOM OR STRATIFIED RANDOM SAMPLING. FOR ALL FORMS OF SAMPLING USED, STRATIFIED RANDOM SAMPLING WITH OPTIMUM ALLOCATION REQUIRED THE SMALLEST SAMPLE RATES FOR A GIVEN ORDER OF ACCURACY AND SIMPLE CLUSTER SAMPLING REQUIRED THE LARGEST. ESTIMATED SAMPLE SURVEY COSTS REQUIRED FOR AN ESTIMATE OF THE TOTAL COST OF THE NEEDS FOR FIVE ORDERS OF ACCURACY WERW ALSO INVESTIGATED FOR EACH SAMPLE METHOD STUDIED. VERY LITTLE DIFFERENCE IN SAMPLING SURVEY COSTS WAS FOUND BETWEEN THE COST FOR SIMPLE RANDOM SAMPLING AND STRATIFIED RANDOM SAMPLING WITH OPTIMUM AND PROPORTIONAL ALLOCATION. ALL FORMS OF CLUSTER SAMPLING, HOWEVER, REQUIRED MUCH GREATER EXPENDITURES TO OBTAIN A NEEDS ESTIMATE WITH A COMPARABLE MARGIN OF ERROR AND A RISK TO THAT USED FOR SIMPLE AND STRATIFIED RANDOM SAMPLING. IT WAS CONCLUDED FROM THIS WORK THAT SAMPLE SURVEY TECHNIQUES FOR THE ESTIMATION OF TOTAL HIGHWAY NEEDS ON COUNTY ROAD SYSTEMS IN AN ENTIRE STATE ARE PRACTICAL. /AUTHOR/

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  • Accession Number: 00200248
  • Record Type: Publication
  • Files: TRIS, TRB
  • Created Date: Sep 16 1994 12:00AM