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Traffic engineering -- Simulation methods, Traffic signs and signals


Transit signal priority (TSP) can reduce transit delay at signalized intersections by making phasing adjustments. TSP is a relatively inexpensive and easy to implement tool to make transit service faster and more reliable. TSP also sends a signal that a city or region encourages the growth of transit mode split. With the aim of assessing the performance of an existing TSP system, this study had access to a unique set of high-resolution bus and traffic signal data. Novel algorithms and performance measures to measure TSP performance are proposed. Results indicate that a timely and effective TSP system requires a high degree of sophistication, monitoring and maintenance. Empirical data suggest that most TSP phase adjustments were granted within the same cycle when buses request priority but that only a small proportion resulted in reduced delay. In this study, many green extension (GE) phases were granted late making them less effective than early (EG) signal phases. Despite this, the TSP system did not increase delays for passengers and vehicles when side street traffic is considered.


Submitted for presentation and publication to the 94th Annual Meeting of the Transportation Research Board (January 2015) and the Journal of Transportation Research Record. This is the authors version of the work. Available online at:



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