Award Abstract # 1446435
CPS: Synergy: Collaborative Research: Control of Vehicular Traffic Flow via Low Density Autonomous Vehicles

NSF Org: CNS
Division Of Computer and Network Systems
Recipient: UNIVERSITY OF ARIZONA
Initial Amendment Date: August 28, 2014
Latest Amendment Date: May 24, 2017
Award Number: 1446435
Award Instrument: Standard Grant
Program Manager: David Corman
CNS
 Division Of Computer and Network Systems
CSE
 Directorate for Computer and Information Science and Engineering
Start Date: January 1, 2015
End Date: December 31, 2018 (Estimated)
Total Intended Award Amount: $280,000.00
Total Awarded Amount to Date: $280,000.00
Funds Obligated to Date: FY 2014 = $280,000.00
History of Investigator:
  • Roman Lysecky (Principal Investigator)
    rlysecky@ece.arizona.edu
  • Jonathan Sprinkle (Former Principal Investigator)
Recipient Sponsored Research Office: University of Arizona
845 N PARK AVE RM 538
TUCSON
AZ  US  85721
(520)626-6000
Sponsor Congressional District: 07
Primary Place of Performance: University of Arizona
AZ  US  85721-0001
Primary Place of Performance
Congressional District:
07
Unique Entity Identifier (UEI): ED44Y3W6P7B9
Parent UEI:
NSF Program(s): CPS-Cyber-Physical Systems
Primary Program Source: 01001415DB NSF RESEARCH & RELATED ACTIVIT
Program Reference Code(s): 8235
Program Element Code(s): 791800
Award Agency Code: 4900
Fund Agency Code: 4900
Assistance Listing Number(s): 47.070

ABSTRACT

In the next few decades, autonomous vehicles will become an integral part of the traffic flow on highways. However, they will constitute only a small fraction of all vehicles on the road. This research develops technologies to employ autonomous vehicles already in the stream to improve traffic flow of human-controlled vehicles. The goal is to mitigate undesirable jamming, traffic waves, and to ultimately reduce the fuel consumption. Contemporary control of traffic flow, such as ramp metering and variable speed limits, is largely limited to local and highly aggregate approaches. This research represents a step towards global control of traffic using a few autonomous vehicles, and it provides the mathematical, computational, and engineering structure to address and employ these new connections. Even if autonomous vehicles can provide only a small percentage reduction in fuel consumption, this will have a tremendous economic and environmental impact due to the heavy dependence of the transportation system on non-renewable fuels. The project is highly collaborative and interdisciplinary, involving personnel from different disciplines in engineering and mathematics. It includes the training of PhD students and a postdoctoral researcher, and outreach activities to disseminate traffic research to the broader public.

This project develops new models, computational methods, software tools, and engineering solutions to employ autonomous vehicles to detect and mitigate traffic events that adversely affect fuel consumption and congestion. The approach is to combine the data measured by autonomous vehicles in the traffic flow, as well as other traffic data, with appropriate macroscopic traffic models to detect and predict congestion trends and events. Based on this information, the loop is closed by carefully following prescribed velocity controllers that are demonstrated to reduce congestion. These controllers require detection and response times that are beyond the limit of a human's ability. The choice of the best control strategy is determined via optimization approaches applied to the multiscale traffic model and suitable fuel consumption estimation. The communication between the autonomous vehicles, combined with the computational and control tasks on each individual vehicle, require a cyber-physical approach to the problem. This research considers new types of traffic models (micro-macro models, network approaches for higher-order models), new control algorithms for traffic flow regulation, and new sensing and control paradigms that are enabled by a small number of controllable systems available in a flow.

PUBLICATIONS PRODUCED AS A RESULT OF THIS RESEARCH

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M. Segata, Cigno, R. Lo, Bhadani, R., Bunting, M., and Sprinkle, J., "A LiDAR Error Model for Cooperative Driving Simulations" IEEE Vehicular Network Conference , 2018
R. Bhadani, Piccoli, B., Seibold, B., Sprinkle, J., and Work, D. B., "Dissipation of Emergent Traffic Waves in Stop-and-Go Traffic Using a Supervisory Controller" IEEE Conference on Decision and Control , 2018
R. Bhadani, Sprinkle, J., and Bunting, M. "The CAT Vehicle Testbed: A Simulator with Hardware in the Loop for Autonomous Vehicle Applications" Proceedings 2nd International Workshop on Safe Control of Autonomous Vehicles (SCAV 2018) , v.269 , 2018
R. Stern, S. Cui, M. L. Delle Monache, R. Bhadani, M. Bunting, M. Churchill, N. Hamilton, R. Haulcy, H. Pohlmann, F. Wu, B. Piccoli, B. Seibold, J. Sprinkle, D. Work. "Dissipation of stop-and-go waves via control of autonomous vehicles: Field experiments." Transportation Research Part C: Emerging Technologies , v.89 , 2018 , p.205

PROJECT OUTCOMES REPORT

Disclaimer

This Project Outcomes Report for the General Public is displayed verbatim as submitted by the Principal Investigator (PI) for this award. Any opinions, findings, and conclusions or recommendations expressed in this Report are those of the PI and do not necessarily reflect the views of the National Science Foundation; NSF has not approved or endorsed its content.

 

Phantom traffic jams - the ones that seemingly occur without an obvious cause like a bottleneck or incident - can be created by the collective human driving behavior alone. Since automated vehicles can take over some driving tasks such as speed control from humans, they may be able to reduce the occurrence of these jams, if those vehicles are properly designed.  This project explored the possibility of automated vehicles to reduce the presence of phantom traffic jams in settings when only as few as 5% of the vehicles are automated, and the rest remain under human control. The project delivered new mathematical models and control algorithms that were demonstrated in theory, computer simulations, and field experiments to eliminate phantom traffic jams. Using a real automated vehicle and more than 20 human drivers, field experiments were conducted that validated the concept that automated vehicles can in fact smooth traffic flow.

The main findings of the project are as follows.

  • A small fraction of automated vehicles can dramatically reduce the presence of phantom traffic jams. A video of the main experiment is available here:  https://youtu.be/2mBjYZTeaTc. A video explaining the research and the experiment is here:  https://youtu.be/CKo-v_qwJwo.

  • Compared to when the phantom jam was present, when the autonomous vehicle removed the jam, the total fuel consumed by all vehicles in the experiment was reduced by approximately 40%. The finding demonstrates that the benefits of automated vehicles may begin to occur even before all vehicles are automated.

  • Based on fuel consumption models applied to the vehicle trajectories it was found that the wave-dampening by the automated vehicle can reduce the vehicles? emissions of harmful nitrogen oxides by up to to 70%.

  • Additional experiments were conducted to assess the jam-absorbing potential of current adaptive cruise control systems on commercial 2018 model year vehicles. The experiments identified that current systems are not able to dampen phantom jams, suggesting more improvements are needed in the design of commercial systems before the potential benefits to traffic are realizable.

Additional project research findings and outcomes are available at the project website: https://phantomjams.github.io.

 

 


Last Modified: 03/27/2019
Modified by: Roman Lysecky

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