Traffic Performance Analysis of Dynamic Merge Control Using Microsimulation

Dynamic merge control (DMC) can be used in freeway merge areas to change lane allocation dynamically at interchanges. DMC generally prioritizes the facility having higher volume and closes a lane on the lesser-volume roadway. DMC has been implemented in the Netherlands and Germany, where it was reported that the application of DMC significantly improved traffic operations. However the DMC strategy has rarely been studied and has not been implemented in the United States. This research used microsimulation studies with VISSIM to investigate the efficiency of the DMC strategy. Optimum traffic demand thresholds were sought specifically for the geometric case in which a two-lane freeway merged with a three-lane freeway and tapered into four lanes. Major-road traffic demands between 2,500 and 4,600 vehicles per hour were compared against minor-road demands between 3,000 and 4,600 vehicles per hour. The DMC strategy was applied by closing the right lane of the major road, ahead of the merging gore area. The results indicate that (a) the DMC strategy is beneficial for all the previously mentioned traffic demand combinations in regard to average vehicle delay and average vehicle speed; (b) when traffic demand on the minor road exceeds 1,900 vehicles per hour per lane, these benefits become statistically and practically significant; and (c) DMC can greatly alleviate the capacity reductions caused by lane changing in the merge area.