A Topology Model: Towards Dense Freeway Network with Resource-Constrained Corridors

Influenced by social development, geographic features, national policies and other factors, the freeway network structure in some regions has been complex and diversified. In addition, land resources are quite limited in areas with the high network density. Existing research on road network topology model has not considered context sensitive information within the corridor zone where selection criteria of design indexes are still unclear. Some new road design concepts have been proposed in previous studies; however they are difficult to apply in practice due to the limitations of models and algorithms the studies used. Based on the topology model which may sufficiently consider spatially sensitive information and index flexibility design in corridors, a new freeway network topology model is proposed for the dense freeway network with resource-constrained corridors. In this model, different geometric design parameters are considered including road horizontal width and vertical elevation. Algorithms for these geometric design parameters are constructed to topological units of curved bin geometry (CBG), curved bin geometry of ramp (RCBG) and junction bin geometry (JBG). Ordinary road segment can be described in the order of CBG units, and the interchanges are mapped by RCBG and JBG units. Meanwhile, the model also considers surrounding road facilities (such as road sign and marking). In order to visualize the model, the data structure model of topology structure is constructed by using the doubly linked list. The topology model was applied to the regional road network in the city of Jiangmen using the ArcGIS platform. This paper provides a scientific and rational basic research model for the application research of safety and reliability, flexibility design or spatial structure optimization in dense freeway network under the condition of resource constraints in corridors.