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Performance Evaluation of a ‘Priority-Controlled’ Intersection Converted to Signal-Controlled Intersection

Authors: Ezenwa Chinenye Amanamba


There is a call to ensure that the issues of safety and efficient throughput are considered during design; the solutions to these issues can also be retrofitted at locations where they were not captured during design, but have become problems to road users over time. This paper adopts several methods to analyze the performance of an intersection which was formerly a ‘priority-controlled’ intersection, but has now been converted to a ‘signal-controlled’ intersection. Extensive review of literature helped form the basis for result analysis and discussion. The Ikot-Ekpene/Anagha-Ezikpe intersection, located at the heart of Umuahia was adopted as case study; considering the high traffic volume on the route. Anecdotal evidence revealed that traffic signals imposed enormous delays at the intersection, especially for traffic on the major road. The major road has arrival flow which surpasses the saturation flow obtained from modelling of the isolated signalized intersection. Similarly, there were several geometric elements that did not agree with the specific function of the road. A roundabout, particularly flower roundabout was recommended as a better traffic control measure.

Keywords: Highway function, level of service, roundabout, traffic delays, Umuahia.

Digital Object Identifier (DOI):

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[1] AASHTO (American Association of State Highway and Transportation Officials). 2001. A Policy on Geometric Design of Highways and Streets, 4th edition. AASHTO, Washington, U.S.A.
[2] Bell, M. C., and Bretherton, R. D. 1986. Ageing of Fixed Time Plans, Proceedings of the 2nd Institution of Electrical Engineers (IEE) Conference on Road Traffic Control, Institution of Electrical Engineers, London, U.K.
[3] Brilon, W. 2011. Studies on Roundabouts in Germany: Lessons Learned, Paper presented at the 3rd International Transport Research Board – Roundabout Conference, Carmel, Indiana.
[4] DfT (Department for Transport). 1995. Design Manual for Roads and Bridges: Road Geometry. TD 42/95. HMSO, London.
[5] FHWA (Federal Highway Administration). 2000. Roundabouts: An Informational Guide. FHWA, Washington, U.S.A.
[6] IHT (Institution of Highways and Transportation). 1987. Roads and Traffic in Urban Areas. IHT, London, U.K.
[7] ITE (Institute of Transportation Engineers). 1989. Toolbox for Alleviating Traffic Congestion. ITE, Washington, U.S.A.
[8] Kimber, R. M., McDonald, M. and Hounsell, N. B. 1986. The Prediction of Saturation Flows for Road Intersections Controlled by Traffic Signals, Research Report 67. Transport Research Laboratory, Crowthorne, U.K.
[9] MoT (Ministry of Transport). 2013. Highway Design Manual; Part 1: Design, Volume 1: Geometric Design. MoT, Abuja, Nigeria.
[10] MoTO (Ministry of Transport, Ontario). 2012. Ontario Traffic Manual: Book 12 – Traffic Signals. MoTO, Ontario, Canada.
[11] Phillips, G. 1979. Accuracy of Annual Traffic Flow Estimates from Short Period Counts, SR514, Transport Research Laboratory. Crowthorne, U.K.
[12] Spiller, N. 1997. Access Management Principles: Introduction and Overview. Federal Highway Administration, Washington, U.S.A.
[13] Tollazzi, T., Renčelj, M., and Turnšek, S. 2011. New Type of Roundabout: Roundabout with ‘Depressed’ Lanes for Right Turning – ‘Flower Roundabout’, Promet – Traffic & Transportation, 23(5), 353-358.
[14] TRB (Transportation Research Board). 2000. Highway Capacity Manual, 4th Edition. TRB, Washington, U.S