Traffic Congestion Measurement Based on Inflow and Outflow Rates

To set up a new traffic congestion measurement for traffic congestion management,which must be quantitative,active,related with direct causes and non-subjective,the shortages of the congestion measurements nowadays are argued.It is proposed to measure the occurrence,expansion and severity of traffic congestion with inflow and outflow rates as well as their duration among established spacial scale.Aiming at congestion emerging process,the traffic congestion definition and the basic cell calculation model based on inflow and outflow rates are presented to unify the measurement forms of smooth flow,compressed flow,stopping and queuing flow.The calculation models of link,intersection and network congestion degree are presented.The theoretical analysis and numerical simulation indicate that the proposed model and method can quantify each congestion states from congestion emerging to coming into being,until its disappearing with continuously numerical values from 0 to 1 and more than 1.Such congestion measurement is dynamic and predictive.The general direction and methodology to stretch and deepen the theories and methods for practical applications are also marked out.