CityX is a research lab led by Dr. Meead Saberi at University of New South Wales (UNSW) Sydney, under the Research Centre for Integrated Transport Innovation (rCITI). Our research focuses on improving scientific understanding of smart cities through development and application of data-model driven methods to better plan, manage and operate urban transport systems.
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Recently Published
Optimal distance- and time-dependent area-based pricing with the Network Fundamental DiagramTransportation Research Part C: Emerging Technologies 95
https://www.sciencedirect.com/science/article/pii/S0968090X18300573 Abstract. Given the efficiency and equity concerns of a cordon toll, this paper proposes a few alternative distance-dependent area-based pricing models for a large-scale dynamic traffic network. We use the Network Fundamental Diagram (NFD) to monitor the network traffic state over time and consider different trip lengths in the toll calculation. The first model is a distance toll that is linearly related to the distance traveled within the cordon. The second model is an improved joint distance and time toll (JDTT) whereby users are charged jointly in proportion to the distance traveled and time spent within the cordon. The third model is a further improved joint distance and delay toll (JDDT) which replaces the time toll in the JDTT with a delay toll component. To solve the optimal toll level problem, we develop a simulation-based optimization (SBO) framework. Specifically, we propose a simultaneous approach and a sequential approach, respectively, based on the proportional-integral (PI) feedback controller to iteratively adjust the JDTT and JDDT, and use a calibrated large-scale simulation-based dynamic traffic assignment (DTA) model of Melbourne, Australia to evaluate the network performance under different pricing scenarios. While the framework is developed for static pricing, we show that it can be easily extended to solve time-dependent pricing by using multiple PI controllers. Results show that although the distance toll keeps the network from entering the congested regime of the NFD, it naturally drives users into the shortest paths within the cordon resulting in an uneven distribution of congestion. This is reflected by a large clockwise hysteresis loop in the NFD. In contrast, both the JDTT and JDDT reduce the size of the hysteresis loop while achieving the same control objective. We further conduct multiple simulation runs with different random seed numbers to demonstrate the effectiveness of different pricing models against simulation stochasticity. However, we postulate that the feedback control is not applicable with guaranteed convergence if the periphery of the cordon area becomes highly congested or gridlocked. |
Urban data visualization, analytics,
modeling, and simulation
SELECTED PROJECTS
We develop advanced dynamic models of large-scale networks, specifically simulation-based dynamic traffic assignment with advanced features such as road pricing and perimeter control.
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Changing Melbourne 2.0 uses visual analytics to demonstrate how socio-demographic characteristics of Melbourne are changing over time using data from ABS Census 2006 and 2011.
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800,000 people moving around Melbourne everyday. This project provides insights into the spatial-temporal distribution of pedestrian activities and crashes in Melbourne.
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This project builds modeling tools to evaluate the impact of different congestion pricing schemes on Melbourne network traffic to inform transport pricing policies.
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Here, we describe the science behind urban network traffic jams, known as network traffic flow theory using our Melbourne DTA model.
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Places by Metro is an interactive application reinventing public transport users experience, connecting businesses to travelers across Melbourne.
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This project aims to develop a new model to measure housing and transport affordability in Australia, with greater Melbourne selected as the pilot study area.
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Large scale demand for travel between origins and destinations in a city can be visualized and analyzed as a complex network.
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The map visualizes the spatial distribution of Average Daily Truck Traffic (ADTT) in Melbourne in 2012.
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To learn more about our ongoing and completed projects, please visit the Research page.
PhD Positions
We are continuously looking for talented and young students to join our research group to do a PhD in Transportation. UNSW offers postgraduate research scholarships to competitive applicants covering tuition fees and an annual stipend of $27,082 plus a possible top up and conference travel grant. If you are interested, please email us your resume.
Our research is recognized and supported by
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