A PREDICTIVE MODEL FOR TRAVEL TIMES ON TWO-LANE STATE HIGHWAYS

PREDICTING TRAVEL TIME ON HIGHWAYS IS ESSENTIAL IN EVALUATING THE LEVEL OF SERVICE, THE ADEQUACY OF THE HIGHWAY SYSTEM, ROAD USER COSTS, AND THE MAGNITUDE OF IMPROVEMENT NEEDED. DETERMINING THE EFFECTS OF FACTORS SUCH AS TRAFFIC, GEOMETRIC CONDITIONS, AND PAVEMENT STRUCTURAL CONDITIONS ON TRAVEL TIME ON TWO-LANE RURAL HIGHWAYS WAS THE TASK OF THIS INVESTIGATION. A STRATIFIED SAMPLE OF 120 HIGHWAY SECTIONS ON INDIANA RURAL STATE HIGHWAYS WAS SELECTED, AND TRAVEL TIME WAS MEASURED BY THE AVERAGE-CAR METHOD. SEVERAL RUNS IN BOTH DIRECTIONS WERE MADE TO OBTAIN REPRESENTATIVE AVERAGE RUNNING TIMES. PARAMETERS SUCH AS TRAFFIC VOLUMES, WIDTH OF PAVEMENT, ETC., WERE MEASURED; OTHER VARIABLES DESCRIBING ROADWAY CHARACTERISTICS, SUCH AS TERRAIN, LENGTH OF NO-PASSING ZONES, ETC., WERE OBTAINED FROM THE RECORDS OF THE SUFFICIENCY INVENTORY OF RURAL STATE HIGHWAYS. TEN SUCH VARIABLES WERE USED IN DATA ANALYSIS. THE AVERAGE RUNNING SPEED WAS THE DEPENDENT VARIABLE IN THE STEPWISE LINEAR REGRESSION ANALYSIS USED TO INTERPRET TRAVEL TIME AS A FUNCTION OF PHYSICAL AND TRAFFIC ROADWAY CONDITIONS. A MODEL CONTAINING ONLY SIX INDEPENDENT VARIABLES (TRAFFIC VOLUME, TRAFFIC INTERRUPTIONS PER MILE, WIDTH OF PAVEMENT, STOPPING SIGHT DISTANCE RESTRICTIONS, ALIGNMENT FACTOR, AND RESTRICTED PASSING SIGHT DISTANCE) PREDICTED RUNNING SPEEDS WITH A HIGH DEGREE OF ACCURACY R SQUARED = 0.903 AND STANDARD ERROR OF ESTIMATE OF 1.876 MPH. THE MODEL WAS THEN TESTED, EXAMINED FOR VARIATION, AND COMPARED WITH SPEED AND VOLUME RELATIONSHIPS SUGGESTED BY THE HIGHWAY CAPACITY MANUAL. /AUTHOR/

  • Supplemental Notes:
    • No 19, 23 PP, 1 TAB, 2 APP
  • Corporate Authors:

    Purdue University/Indiana Department of Transportation JHRP

    Purdue University, School of Civil Engineering
    West Lafayette, IN  United States  47907-1284
  • Authors:
    • Hejal, S S
    • Michael, H L
  • Publication Date: 0

Subject/Index Terms

Filing Info

  • Accession Number: 00228044
  • Record Type: Publication
  • Files: TRIS
  • Created Date: May 3 1971 12:00AM