LAG AND GAP ACCEPTANCES AT STOP-CONTROLLED INTERSECTIONS

Abstract

THE PURPOSE OF THIS RESEARCH STUDY WAS TO INVESTIGATE THE LAG AND GAP ACCEPTANCES FOR DRIVERS ENTERING AND CROSSING A MAJOR ROADWAY FROM A STOPPED POSITION. THIS DRIVER-BEHAVIOR EVALUATION INCLUDED A DETERMINATION OF A LAG-AND-GAP ACCEPTANCE DISTRIBUTION FOR THE SIDESTREET DRIVERS, CONSIDERATION OF COMMUNITY INFLUENCE ON THIS DISTRIBUTION, AND COMPARISONS OF TIME-INTERVAL ACCEPTANCES BY DRIVERS MAKING THROUGH, LEFT-TURN, AND RIGHT-TURN MOVEMENTS. THE STUDY WAS PERFORMED AT RIGHT-ANGLE INTERSECTIONS FORMED BY TWO-WAY, TWO-LANE, URBAN STREETS. FOUR SITES, SELECTED IN LAFAYETTE AND INDIANAPOLIS, IND., WERE AS IDENTICAL AS POSSIBLE REGARDING GEOMETRY AND ADJACENT LAND USE. THE DATA WERE COLLECTED AT THESE SITES BY MEANS OF A MOTION PICTURE CAMERA. THE TECHNIQUE OF PROBIT ANALYSIS WAS EMPLOYED IN THE STATISTICAL TREATMENT OF THE OBSERVATIONS. IN ADDITION, TWO OTHER METHODS, ONE DEVELOPED BY RAFF AND THE OTHER BY BISSELL, WERE CONSIDERED IN THIS EVALUATION OF DRIVER BEHAVIOR AT STOP-CONTROLLED INTERSECTIONS. THE ACCEPTANCE DISTRIBUTIONS WERE WELL DESCRIBED BY A LINEAR RELATIONSHIP BETWEEN THE PROBIT OF ACCEPTANCE AND THE LOGARITHM OF ACCEPTANCE TIME. THERE WAS NO SIGNIFICANT DIFFERENCE BETWEEN THE MEDIAN LAG-ACCEPTANCE AND THE MEDIAN GAP- ACCEPTION TIMES AT THE FOUR INTERSECTIONS. HOWEVER, SIGNIFICANT VARIATIONS WERE FOUND BETWEEN RIGHT-AND LEFT- TURNING DRIVERS AND BETWEEN DRIVERS PROCEEDING THROUGH THE INTERSECTION AND THOSE MAKING LEFT TURNS. RIGHT-TURNING DRIVERS AND THOSE CROSSING THE INTERSECTION HAD STATISTICALLY EQUAL MEDIAN ACCEPTANCE TIMES. COMMUNITY SIZE APPARENTLY HAS SOME INFLUENCE ON DRIVER PERFORMANCE AT INTERSECTION APPROACHES CONTROLLED BY STOP SIGNS. A GENERAL AGREEMENT EXISTED AMONG THE THREE METHODS OF ANALYSIS INVESTIGATED. /AUTHOR/