Research Projects

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Research Projects

STATUS: Complete YEAR: 2020 TOPIC AREA: Public transit, land use, and urban mobility CENTER: PSR

Data-driven Feedback Control of Urban Traffic Systems with Performance Guarantees

Project Summary

Project number: PSR-20-17
Funding source: US DOT
Contract number: 69A3551747109
Funding amount: $100,000
Performance period: 8/16/2020- 12/31/2021

Link to full seminar video

Project Description

The project objectives are:
  1. Model traditional and emerging sensing along with traffic flow dynamics in a common frame-work, in which traffic signal, variable speed limit, ramp metering and routing control usesensor measurements directly.
  2. Evaluate sub-optimality, from the perspective of real-time performance, of the commonly usedapproach which first inaccurately estimates the traffic state (queue length, traffic volume, etc.)from sensor measurements and inputs it into control algorithms.
  3. Develop a new framework that jointly selects optimal estimation and control algorithms toimprove performance of the overall data-driven control of urban traffic systems.
  4. Simulation case studies in PTV VISSIM to evaluate the efficacy of the proposed approach.

The increasing penetration rate of GPS enabled personal mobile devices and connected vehiclesis leading to new sensing modes in urban traffic systems. This has spurred interest in methodologiesto estimate relevant traffic state such as traffic density, queue length, and travel time, to be usedas input to traffic control strategies, such as traffic signal control, variable speed limit, rampmetering, and routing. However, the impact of the correlation of measurements from these andtraditional sensing modes with relevant information about traffic state, and of the accuracy of real-time estimates on performance, e.g., in terms of energy consumption, emissions, throughputand travel time, is not understood rigorously. Correspondingly, there does not exist a principledapproach for joint choice of estimation and control algorithms to optimize performance of urbantraffic systems. In this project, we aim to develop methodologies to overcome this shortcoming.

We shall first provide analytical guarantees on key performance metrics for freeway and signal-ized networks, including travel time and emissions, under the commonly used approach to simplycombine independently designed estimation and control algorithms. We shall then consider si-multaneous choice of estimation and control algorithms that optimize end-to-end performance ofurban traffic systems, and which are amenable to distributed implementation. The key enablers ofour methodologies will be recent developments in feedback optimal and model predictive controltheory, and in adaptation of distributed optimization algorithms for control of traffic flow. Theanalysis will provide fundamental insights into how the quality of measurements, in terms of noiseand correlation with the underlying traffic state of interest, interplays with the traffic flow dynam-ics to determine performance of the overall data-driven control framework. Extensions to settingswhere key traffic parameters, such as wave speed, jam density and saturation flow, are unknownor uncertain will also be pursued. Case studies in PTV VISSIM for setups inspired by the LosAngeles area will augment the methodological contributions.

Research seminar highlights video


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]