A Method for Evaluating the Functional Hierarchy of Road Networks by using Road Use Characteristic Indices

Abstract

The concept of a functional hierarchical road network is important as one of the solutions to the road traffic problems that still occur in Japan, where the road network has been steadily developed. This study aims to propose a method to evaluate in which degree of functional hierarchy the road network is being used. In a virtual road network with three levels of hierarchy, the shortest routes are searched under the free flow conditions, and the road use characteristic indices are calculated such as trip lengths and use rates of each hierarchical level. Based on the conditions of the road network represented by these index values, a method to evaluate its functional hierarchy in four degrees is proposed. As a case study, the degree of hierarchy was calculated for the road networks in southern Gifu and western Shizuoka. The results revealed that the current evaluations of the functional hierarchy in these areas were low, and that the mid-level roads are required for improving the current situation.