Speed-Volume Relationship Model for Speed Estimation on Urban Roads in Intelligent Transportation Systems

Estimating average speed on roads is required by many applications in Intelligent Transportation Systems. In spite of abundant researches done on speed estimation on highways, there is only limited effort made in urban traffic networks. Current reserach methodology is to apply highway models to urban roads directly or under trivial modification. In this paper, we propose a novel speed estimation model tailored for urban roads. The contribution of this work includes the following two aspects: 1)we demonstrate that application of modified highway models to urban roads is not always an effective methodology; 2)we propose a speed-volume relationship model tailored for speed estimation on urban roads by incorporating the impedance effect of exit intersection of a concerned road. We have applied the model to estimate the speed in Cologne, Germany, compared the accuracy between the proposed model and a slightly modified Greenshield’s Model, and confirmed its effectivity as well as superiority.