THE EFFECT OF PLATOON DISPERSION ON THE PERFORMANCE OF ROUNDABOUTS AND UNSIGNALISED INTERSECTIONS: A STUDY OF EXISTING PLATOON DISPERSION MODELS

Road networks in urban areas are becoming more congested as the number of commuters using them increases. To increase the capacity of these networks, without resorting to reconstruction, they need to be analysed as a whole, rather than as separate components. Methods for the analysis of signalised intersections networks have been developed which enable those networks to be linked so as to achieve minimum total delays and maximum capacity. To date no method has been developed to include roundabouts or unsignalised intersections within arterial road networks. New design methods based upon gap acceptance have been developed recently for the analysis of roundabouts and unsignalised intersections. These methods use the headway distributions to model the traffic flow on the intersection approaches. When a signalised intersection is located near a roundabout or unsignalised intersection, the performance of that intersection is affected. This paper describes research currently underway, aimed at developing a model describing the changes in the headway distribution as the distance from the signalised intersection increases. (A)