A Multi-Hierarchical Strategy for On-Ramp Coordination

R. Jiang, J.B. Lee, Edward Chin Shin Chung

Research output: Journal article publicationJournal articleAcademic researchpeer-review

5 Citations (Scopus)


© 2015, Springer Science+Business Media New York.Ramp metering (RM) is an access control for motorways, in which a traffic signal is placed at on-ramps to regulate the rate of vehicles entering the motorway and thus to preserve the motorway capacity. In general, RM algorithms fall into two categories by their effective scope: local control and coordinated control. Local control algorithm determines the metering rate based on the traffic condition on adjacent motorway mainline and the on-ramp. Conversely, coordinated RM strategies make use of measurements from the entire motorway network to operate individual ramp signals for optimal performance at the network level. This study proposes a multi-hierarchical strategy for on-ramp coordination. The strategy is structured in two layers. At the higher layer, a centralised, predictive controller plans the coordination control within a long update interval based on the location of high-risk breakdown flow. At the lower layer, reactive controllers determine the metering rates of those ramps involved in the ramp coordination with a short update interval. This strategy is modelled and applied to the northbound model of the Pacific Motorway in a micro-simulation platform (AIMSUN). The simulation results show that the proposed strategy effectively delays the onset of congestion and reduces total congestion with better managed on-ramp queues.
Original languageEnglish
Pages (from-to)50-62
Number of pages13
JournalInternational Journal of Intelligent Transportation Systems Research
Issue number1
Publication statusPublished - 1 Jan 2017
Externally publishedYes


  • Micro-simulation
  • Ramp coordination
  • Ramp metering

ASJC Scopus subject areas

  • General Neuroscience


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