Vehicle–space traffic-state estimation of a motorway corridor with slip roads

Abstract

Traffic-state estimation is a key component of an advanced traffic management system. The Eulerian traffic-state estimation based on an X-T traffic-flow model has proved successful in processing traditional X-T data sources such as inductive loop data. However, over the past decade, the emergence of probe vehicle data from paired sensors has created challenges for X-T traffic-state estimation. The vehicle–space (N-X) model has shown potential benefits in modelling paired-probe data. In this paper, an original N-X traffic-state estimation framework is proposed and validated by numerical experiments. In addition, an original first-order conservation formulation is derived to address the entry and exit slip road issue for motorway corridors. An evaluation is conducted by comparing the proposed N-X estimation with the X-T estimation. The results show that the proposed model is superior to the X-T estimation in terms of accuracy and efficiency. It performs well, particularly during congestion, and can track traffic breakdowns and recoveries effectively.