Lane-free Artificial-Fluid Environment for Vehicular Traffic

Project Information

TrafficFluid

Grant agreement ID: 833915

DOI

10.3030/833915

Project closed

EC signature date 25 April 2019

Start date 1 December 2019

End date 30 November 2025

Funded under

• EXCELLENT SCIENCE - European Research Council (ERC)

Total cost

€ 2 495 500,00

EU contribution

€ 2 495 500,00

Coordinated by

POLYTECHNEIO KRITIS
Greece

Periodic Reporting for period 4 - TrafficFluid (Lane-free Artificial-Fluid Environment for Vehicular Traffic)

Reporting period: 2024-06-01 to 2025-11-30

Summary of the context and overall objectives of the project

Road traffic congestion is a serious threat to the economic and social life of modern societies as well as to the environment. To effectively improve road capacity, traffic safety, fuel consumption and environmental impact, the TrafficFluid project launched and investigated a novel paradigm for vehicular traffic in the era of connected and automated vehicles (CAVs), which is based on two combined principles.
• The first principle is lane-free traffic, which: renders the driving task for CAVs smoother and safer, as risky lane-changing maneuvers become obsolete; increases the capacity of the roadway due to increased lateral road occupancy; mitigates congestion-triggering maneuvers; and enables flexible sharing of the road infrastructure among the two traffic directions.
• The second principle is the nudge effect, whereby vehicles may be "pushing" (from a distance, using sensors or communication) other vehicles all around them. This allows for CAV traffic to be freed from the restriction of human driving to be influenced only by downstream vehicles (anisotropy). The nudge effect is found to improve traffic flow capacity and stability.

TrafficFluid combines lane-free traffic with vehicle nudging to provide the possibility to design (rather than merely describe or model) the traffic flow characteristics in an optimal way, i.e. to engineer the future CAV traffic flow as an efficient artificial fluid. To this end, the project has developed appropriate vehicle movement strategies for various motorway and urban road infrastructures, along with microscopic simulators, macroscopic modelling of the emerging traffic flow and diverse traffic management actions.

TrafficFluid addressed the challenge of designing a new traffic system from scratch. While pursuing this endeavor, the project has opened a new avenue of related international innovative research developments that pave the way towards a new efficient traffic system in the era of CAVs.

TrafficFluid work was organized in four interconnected Work Packages (WPs):
a) Vehicle Movement Design (WP1) addressed 2-D vehicle movement design so as to guarantee significant properties regarding safety, fuel consumption, passenger convenience and efficiency.
b) Modelling and Simulation (WP2) developed an open-source microscopic simulator as well as macroscopic traffic flow models that allow for analysis and assessment of the designed vehicle movement strategies and emerging traffic features.
c) Extensions and Improvements (WP3) offered additional features and options and diverse urban and highway traffic control measures under the new traffic paradigm, including signal-free urban junction operation.
d) Dissemination (WP4) included a multitude of actions aimed at promoting the ground-breaking character of TrafficFluid research.
Please visit our website www.trafficfluid.tuc.gr for more information. Among others, the website includes several videos illustrating published research results.

Work performed from the beginning of the project to the end of the period covered by the report and main results achieved so far

Achievements of the project exceeded initial plans. Within WP1, we worked in parallel on four methodological avenues to derive efficient vehicle movement strategies, namely using ad-hoc, reinforcement learning, optimal control and nonlinear feedback control approaches. In addition, various lane-free vehicle formations, such as 1-D snake-like vehicle platoons and flexible 2-D vehicle flocks, were designed. Within WP2, the open-source TrafficFluid-Sim microscopic simulator was developed for both highway and urban road network traffic. Also, macroscopic models for lane-free traffic with nudging were developed, both analytically and empirically. Finally, within WP3, pioneering achievements concerned the innovative and very promising internal boundary control (IBC); ramp metering and speed control on highways; and signal-free lane-free urban intersection operation involving CAVs, platoons, pedestrians and cyclists.

Dissemination activities include:
a) The project’s website www.trafficfluid.tuc.gr that will be maintained after the project’s completion.
b) Articles (in the most renowned journals and conferences in the area): 28 journal, 55 conference articles; with some more journal papers to follow.
c) 22 research-related video groups to illustrate research results.
d) Beyond the conference paper presentations, the PI and TrafficFluid members delivered 71 invited presentations at research organisations and scientific events in 22 countries, among them several keynote presentations.
e) Organisation of 8 seminars of external scientists.
f) Organisation of a joint Workshop on "Lane-free Traffic" at the Technical University of Crete by the TrafficFluid project and the Chair of Traffic Engineering and Control, Technical University of Munich, Germany, on 2, 5 and 6 June 2023.
g) Organisation of Special Sessions at conferences and Special Issues at journals.
h) Hosting of 6 visitors from Germany, USA, France, Italy, China and Finland respectively, over 2-4 months each.
i) Several media reports and interviews.

Finally, collaboration with four research groups from: Technical University of Munich, Germany; Zhejiang University, China; ETH Zurich, Switzerland; and Aalto University, Finland was agreed and has been ongoing on issues related to the TrafficFluid paradigm, leading to many joint publications.

The project opened a new promising research and developing area that attracted the interest of many research groups globally. International research is ongoing in this new domain and pilot deployments are planned.

Progress beyond the state of the art and expected potential impact (including the socio-economic impact and the wider societal implications of the project so far)

Given the profoundly innovative scope of the project, virtually all developments and achievements are addressing “new land”, thereby extending the state-of-the-art in automated vehicle movement design, CAV macroscopic traffic flow modelling, traffic management and more. More specifically:
1. Vehicle Movement Design: Beyond "pipeline" highways or circular road, critical circumstances, such as efficient merging, diverging and weaving policies, as well as driving on complex urban roundabouts and signal-free intersections were addressed.
2. Modelling and Simulation: The microscopic simulator TrafficFluid-Sim was developed on the basis of the open-source tool SUMO to cover the needs of the project and of external users. In addition, theoretical development of macroscopic traffic flow models under the TrafficFluid concept, as well as conventional model calibration led to exciting new insights and results.
3. Extensions and Improvements: At vehicle level, the presence of manually driven vehicles or emergency vehicles were investigated. Joint path planning for 1-D snake-like vehicle platoons and 2-D vehicle flocks were developed. At traffic level, we designed and demonstrated traffic control measures to mitigate congestion, such as ramp metering, vehicle speed control and, as an innovative opportunity enabled by the TrafficFluid concept, internal boundary control (IBC). Our investigations show that particularly the novel traffic control measure IBC leads to unprecedented increase in road utilization. At the infrastructure level, signal-free urban junctions and networks and roundabouts were considered, leading to exciting results. We also addressed, as an interesting case study and challenge, the lane-free movement of automated vehicles on a very complex lane-free roundabout, the Charles-de-Gaulle roundabout in Paris, France.

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