ANOTHER LOOK AT IDENTIFYING SPEED-FLOW RELATIONSHIPS ON FREEWAYS.

Despite approximately 50 years of research on highway operating characteristics, the way in which the speed-flow relationship moves between free flow and congested flow conditions is still not clearly understood. The speed-flow relationship as it pertains to those transitions is investigated using an extensive data set collected on the Queen Elizabeth Way freeway in Ontario. Two different analytical approaches are used: time-connected plots of mean speed and mean flow and an event-based trace, averaged with respect to the transition to and from congested flow.