Research Projects

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Research Projects

STATUS: Complete YEAR: 2019 TOPIC AREA: Connected and autonomous systems Sustainability, energy, and health CENTER: PSR

Traffic Flow Models Based on Queuing Theory for Analysis and Performance Evaluation

Project Summary

Project number: PSR-19-17

Funding source: US DOT

Contract number: 69A3551747109

Funding amount: $99,998

Performance period: 5/16/2020 to 07/31/2021

Project Description


The objectives of this project are: 


  • Develop queueing models that take into account microscopic vehicle characteristics
  • Use the models to analyze the performance of transportation networks in both dimensions, space and time
  • Use analysis and rigorous proofs to examine stability of equilibrium states
  • Use simulations and real data to demonstrate the results


Queueing models provide a compelling framework to evaluate performance of traffic systems at macroscopic scale, e.g., in terms of flow, density, and travel times. However, the service paradigms typically used in existing frameworks do not have sufficient resolution to model and differentiate between emerging automation technologies at the microscopic scale. Such inadequacies can translate into erroneous performance estimates at the macro scale. On the other hand, there have been sustained and even renewed efforts on modeling vehicle level dynamics under (automated) car-following and lane-changing protocols, and their impact on traffic flow. The analytical studies along these lines, e.g., platooning and string stability, are typically restricted to closed systems, i.e., with a fixed number of vehicles, and primarily in spatially unbounded settings. While such setups are a good starting point, realistically one needs to account for externalities, in the form of arrival and departures and spatial constraints, attributed to the rest of the traffic system. 


In this project, we propose to develop novel spatial queues for traffic systems, whose service paradigm is modeled explicitly on the basis of microscopic inter-vehicle interactions (car-following and lane-changing) including communication/reaction delay. The setup will be flexible to include heterogeneity in inter-vehicle interactions, e.g., mixed-autonomy, and to include varying levels of connectivity. Rigorous queueing-theoretic analysis for identifying the region of stability and waiting time will be performed, to provide a characterization of capacity and average travel times, respectively, in terms of physical dimensions of the traffic infrastructure, spatio-temporal travel demand profile, and automation and control technologies. Case studies using standard datasets, such as PEMS and NGSIM, as well as using microscopic simulators such as PTV VISSIM, will be used to demonstrate the theoretical results.



Ketan Savla
Assistant Professor, Sonny Astani Department of Civil and Environmental Engineering; USC Viterbi School of Engineering
3620 South Vermont Avenue
Kaprielian Hall (KAP) 254ALos Angeles, CA 90089-2531
United States
[email protected]


Petros Ioannou
Professor of Electrical Engineering Systems, Ming Hsieh Department of Electrical Engineering; USC Viterbi School of Engineering
3740 McClintock Avenue
Hughes Aircraft Electrical Engineering Center (EEB) 200BLos Angeles, CA 90089-2562
United States
[email protected]