Can the Presence of Autonomous Vehicles Worsen the Equilibrium State of Traffic Networks?

Negar Mehr, Roberto Horowitz

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

It is known that autonomous vehicles are capable of maintaining shorter headways and distances when they form platoons of vehicles. Thus, deployment of autonomous vehicles can result in roadway flow capacity increases in traffic networks. Consequently, it is envisioned that their deployment will boost the overall capacity of the network. In this paper, we consider a nonatomic routing game on a traffic network with inelastic (fixed) demands for the set of network O/D pairs, and study how replacing a fraction of regular (i.e. nonautonomous) vehicles by autonomous vehicles will affect the network total delay, under the assumption that the vehicles choose their routes selfishly. Using well known US bureau of public roads (BPR) traffic delay models, we show that the resulting Wardrop equilibrium is not necessarily unique even in its weak sense for networks with mixed autonomy. We derive the conditions under which the total network delay is guaranteed to not increase as a result of increasing the ratio of autonomous vehicles. However, we also show that when these conditions do not hold, counter intuitive behaviors might occur: the total delay can grow by increasing the fraction of autonomous vehicles in the network. In particular, we prove that for networks with a single O/D pair, if the road degree of capacity asymmetry (i.e. the ratio between the road capacity when all vehicles are regular and the road capacity when all vehicles are autonomous) is homogeneous, the total network delay is 1) unique, and 2) a nonincreasing continuous function of network autonomy fraction. We show that for heterogeneous degrees of capacity asymmetry, the total delay is not unique, and it can further grow when the fraction of autonomous vehicles increases. We demonstrate that similar behaviors may be observed in networks with multiple O/D pairs.

Original languageEnglish (US)
Title of host publication2018 IEEE Conference on Decision and Control, CDC 2018
PublisherInstitute of Electrical and Electronics Engineers Inc.
Pages1788-1793
Number of pages6
ISBN (Electronic)9781538613955
DOIs
StatePublished - Jan 18 2019
Externally publishedYes
Event57th IEEE Conference on Decision and Control, CDC 2018 - Miami, United States
Duration: Dec 17 2018Dec 19 2018

Publication series

NameProceedings of the IEEE Conference on Decision and Control
Volume2018-December
ISSN (Print)0743-1546

Conference

Conference57th IEEE Conference on Decision and Control, CDC 2018
CountryUnited States
CityMiami
Period12/17/1812/19/18

ASJC Scopus subject areas

  • Control and Systems Engineering
  • Modeling and Simulation
  • Control and Optimization

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  • Cite this

    Mehr, N., & Horowitz, R. (2019). Can the Presence of Autonomous Vehicles Worsen the Equilibrium State of Traffic Networks? In 2018 IEEE Conference on Decision and Control, CDC 2018 (pp. 1788-1793). [8618919] (Proceedings of the IEEE Conference on Decision and Control; Vol. 2018-December). Institute of Electrical and Electronics Engineers Inc.. https://doi.org/10.1109/CDC.2018.8618919