Abstract:As a case study,three wellknown onramp metering algorithms,including fixedtime,Alinea and Flow,were evaluated via traffic simulation on Shenzhen Chunfeng expressway on various traffic demand levels,the parameters calibrations were also expatiated. Simulation results show that onramp metering can effectively improve mainline traffic when traffic demand is higher than a certain level.Both Alinea and Flow perform better than fixedtime metering,but increase ramp delay and queue obviously. Flow outperforms Alinea in this case study because the traffic bottleneck is closely related to its upstream onramps traffic.Finally,the scenarios of adding queue adjustment into Alinea and Flow were simulated.Results show that the distance of queue detectors to ramp entrance plays a key role to tradeoff between the mainline congestion and onramp queue.
