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Improving SCATS Operation during Congestion Periods Using Internal/External Traffic Metering Strategy
Shahriar Afandizadeh Zargari, Nazli Dehghani, Hamid Mirzahossein, Masoud Hamedi
Keywords:traffic metering, gridlock, signal timing, SCATS subject classification, VISSIM,


Traffic metering is one of the effective strategies of preventing gridlock at urban signalized intersections during oversaturated conditions. This strategy could be implemented by adjusting signal timing schemes of the connected intersections of congested network in dynamic setting. This paper demonstrates the benefits of internal/external traffic metering strategy on a real case study in Tehran, the capital of Iran. For this purpose, the model outputs have been considered as input to set of SCATS scenarios for signal timing. In each test case the system is forced to use plans obtained from the model instead of using common built-in plans that had been used before, and the performance is measured using the VISSIM simulator to show differences. The results show significant improvement in network average travel time when using internal/external traffic metering strategy. Additionally, the average queue lengths are maintained near the optimal level since the model utilizes upstream arterial capacity.


Gal-Tzur A, Mahalel D, Prashker JN. Signal design for congested networks based on metering; 1993.

Lieberman E, Chang J, Prassas E. Formulation of real-time control policy for oversaturated arterials. Transportation Research Record: Journal of the Transportation Research Board. 2000;(1727):77-88.

Daganzo CF. Urban gridlock: macroscopic modeling and mitigation approaches. Transportation Research Part B: Methodological. 2007;41(1):49-62.

Luk J, Green D. Balancing traffic density in a signalised network; 2010.

Keyvan-Ekbatani M, Kouvelas A, Papamichail I, Papageorgiou M. Exploiting the fundamental diagram of urban networks for feedback-based gating. Transportation Research Part B: Methodological. 2012;46(10):1393-403.

He J, Hou Z. Ant colony algorithm for traffic signal timing optimization. Advances in Engineering Software. 2012;43(1):14-8.

Varia H, Gundaliya P, Dhingra S. Application of genetic algorithms for joint optimization of signal setting parameters and dynamic traffic assignment for the real network data. Research in Transportation Economics. 2013;38(1):35-44.

Afandizadeh S, Latifi M, Dehghani N. Real time queue estimation model in saturated urban arterials in Tehran. Journal of transportation research. 2013;4(1):365.

TCTTS TCTaTSC-. Link Performance Function Studies; 2014.

Irannezhad E, Mousavi SH, Moraveji G, editors. Updating OD Matrix based on traffic counts for evaluating traffic management plans in Tehran. Proceedings of 11th International Traffic & Transportation Conference, Tehran, Iran; 2012.

Copyright (c) 2023 Shahriar Afandizadeh Zargari, Nazli Dehghani, Hamid Mirzahossein, Masoud Hamedi

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University of Zagreb, Faculty of Transport and Traffic Sciences
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