Real time adaptive cruise control strategy for motorways

An ACC (Adaptive Cruise Control)-based traffic control strategy is presented, which improves the motorway traffic flow efficiency by changing in real time the driving behaviour (specifically the employed time-gap and the acceleration strength) of ACC-equipped vehicles in motorway sections according to the corresponding traffic conditions. The control strategy comprises three distinct actions: (i) gradual decrease of ACC time-gaps at near-capacity traffic in order to increase capacity; (ii) minimum time-gaps and (iii) acceleration increase, both at the very vicinity of active bottlenecks in order to increase the discharge flow. The behaviour and impact of the control strategy, and of each of its parts separately, are demonstrated for different ACC penetration rates via microscopic simulation applied to a real motorway stretch. The simulation results show that, even for low penetration rates of ACC-vehicles, the proposed strategy leads to sensible improvements regarding the average vehicle delay and fuel consumption by delaying the onset of congestion (thanks to increased capacity); and by speeding up its dissolution (thanks to the mitigation of capacity drop).