The ERC Advanced Grant TrafficFluid (2019-2024) launches 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 manoeuvres become obsolete; increases the capacity of the roadway due to increased road occupancy; and mitigates congestion-triggering vehicle manoeuvres. The second principle is vehicle nudging, whereby vehicles may be "pushing" other vehicles in front of them; this allows for traffic flow to be freed from the anisotropy restriction, which stems from the fact that human driving is influenced only by downstream vehicles. Vehicle nudging may be implemented in various possible ways, so as to enhance the traffic flow efficiency and stability, subject to safety and convenience constraints.

Lane-free CAV traffic implies that incremental road widening (narrowing) leads to corresponding incremental increase (decrease) of capacity. This opens the way for real-time internal boundary control on highways and arterials, in order to flexibly share the total (both directions) road width and capacity among the two directions in dependence of the bi-directional demand and traffic conditions, so as to maximize the total (two directions) flow efficiency. The problem is formulated as a convex QP (Quadratic Programming) or as an LQ-Regulator problem, and representative case studies shed light on and demonstrate the features and potential of the novel control action.

The seminar concludes with the brief presentation of a conventional lane-free case study referring to the Place Charles de Gaulle roundabout in Paris.