THE EFFECTS OF ENVIRONMENTAL CONDITIONS ON DRIVER ON-RAMP MERGING BEHAVIOR

MERGING BEHAVIOR ON RAMPS IS TREATED FROM THE STAND-POINTS OF (1) GAP PERCEPTION AND (2) ENVIRONMENTAL CONDITIONS. MERGING BEHAVIOR ON A RAMP OF THE LONG ISLAND EXPRESSWAY WAS RECORDED PHOTOGRAPHICALLY AND CORRELATED WITH 43 MEASURES OF GAP PERCEPTION. THE MEASURES WERE FORMULATED MATHEMATICALLY ("G" EXPRESSIONS - GE) FROM OBSERVABLE RAMP AND MAINSTREAM-VEHICLE KINEMATICS. THE MAJOR OBJECTIVES WERE TO RANK THESE SUBJECTIVE MEASURES OF GAP SIZE AND TO CORRELATE THEM WITH FOUR ENVIRONMENTAL VARIABLES (DAYTIME, ILLUMINATED DARKNESS, AND DRY AND WET DRIVING CONDITIONS). THE FIRST OF THESE OBJECTIVES WAS APPROACHED THROUGH THE CORRELATION RATIO TECHNIQUE SUPPLEMENTED BY AN ANALYSIS OF AVERAGE ACCEPTANCE/REJECTION BEHAVIOR FOR THE VARIOUS EXPERIMENTAL CONDITIONS. IN ADDITION, PROBIT ANALYSIS WAS USED TO DESCRIBE THE DISTRIBUTION OF MERGING BEHAVIOR FOR ALL VALUES OF THOSE GE DETERMINED TO BE MOST IMPORTANT IN ACCEPTANCE/REJECTION DECISIONS. IT WAS FOUND THAT THESE GE WERE THOSE THAT REFLECTED THE KINEMATICS OF LAG CONDITIONS, THE TWO SHOWING THE HIGHEST CORRELATION ALSO INCLUDING A SAFETY FACTOR, I.E., THE TIME OR DISTANCE REQUIRED FOR THE LAG VEHICLE TO SLOW DOWN TO MATCH THE SPEED OF THE MERGING VEHICLE. OTHER HIGH-CORRELATION GE REFLECTED THE RELATIVE VELOCITY OF RAMP AND MAINSTREAM VEHICLES. WHILE TIME LAG ALSO PROVED TO HAVE A HIGH CORRELATION, THE TIME HEADWAY BETWEEN TWO VEHICLES DEFINING A GAP SHOWED LITTLE CORRELATION. WITH RESPECT TO THE SECOND MAJOR OBJECTIVE, DRIVERS UNDER NIGHT--DRY CONDITIONS PROVED SOMEWHAT MORE CONSERVATIVE THAN UNDER DAY--DRY CONDITIONS. HOWEVER, MERGING BEHAVIOR FOR NIGHT--WET CONDITIONS WAS MORE ANALOGOUS TO THAT FOR DAY--DRY THAN FOR NIGHT--DRY. (AS ONLY ONE HOUR OF NIGHT WET DATA WAS OBTAINED, FURTHER ANALYSIS IS IN ORDER.) THE PROBIT ANALYSIS WAS IN AGREEMENT WITH THESE OBSERVATIONS, INDICATING RELATIVE DRIVER INCONSISTENCY UNDER NIGHT--DRY CONDITIONS.

• Corporate Authors:

  HRB-Singer Incorporated

  P.O. Box 60, Science Park
  State College, PA  United States  16801

  Pennsylvania Department of Highways

  400 North Street
  Harrisburg, PA  United States  17120-0095

  Federal Highway Administration

  1200 New Jersey Avenue, SE
  Washington, DC  United States  20590
• Authors:
  • Carter, R G
  • Root, R T
  • Sequin, E L
  • Avis, G B
• Publication Date: 1970-6

Subject/Index Terms

• TRT Terms: Behavior; Correlation analysis; Days; Distance; Drivers; Dryness; Dynamics; Gap acceptance; Headways; Interchange ramps; Kinematics; Lagging (Earthwork); Merging traffic; Moisture content; Night; Ramps; Statistical analysis; Time; Vehicle dynamics; Vehicles
• Uncontrolled Terms: Dry conditions; Wet conditions
• Old TRIS Terms: Driver psychology; Freeway ramps; Lagging
• Subject Areas: Data and Information Technology; Highways; Operations and Traffic Management; Vehicles and Equipment;

Filing Info

• Accession Number: 00224966
• Record Type: Publication
• Source Agency: Federal Highway Administration
• Report/Paper Numbers: Cpr-11-5934
• Files: TRIS, ATRI, USDOT
• Created Date: Mar 7 1971 12:00AM