Driver Gap Acceptance Phenomena

Results from a field study of gap acceptance characteristics of drivers executed merging maneuvers from stopped positions on side roads to main roads are presented. Gap acceptance parametrs are first estimated from the field data in an aggregated form and then for individual traffic flows observed on the main roads. It is found that flow on the main roads substantially influences the gap acceptance characteristics of drivers on the side roads. The practical implications of this influence on the accurate computations of average delays and intersection capacity, normally based on gap acceptance parameters, are also investigated. It is found that when these values are derived from gap acceptance parameters estimated from the aggregated data; they differ by as much as 20% from those derived from gap acceptance parameters estimated from the disaggregated data.