Evaluating the Capacity of Freeway Weaving Sections

Abstract

The research described in this paper employed simulation modeling and empirical observations in an effort to: (1) Identify the traffic flow phenomena that characterize freeway weaving section capacity; and (2) determine appropriate traffic flow rate values that reflect weaving section capacity. The INTRAS microscopic simulation model was calibrated and validated using empirical data collected at a weaving site. Increasing traffic demands were then sequentially input into repeated simulation runs to identify the boundary between uncongested and congested operation. Where a weaving section exhibits a typical level of both merging and diverging traffic movements, capacity is defined as a function of flows and lane‐changing rates occurring in the vicinity of the weaving area's merge gore. Where a weaving section operates with a relatively low total weaving demand, capacity is defined as a maximum rate of vehicles per lane. Validation experiments described in this paper suggest that the derived values of capacity apply to any one‐sided freeway weaving section.