Towards an Over-the-horizon Awareness to Driver Support Systems in Highway Real-World Scenarios

Aiming at addressing the high level of congestion due to the increasing number of vehicles on roads worldwide, Driver Support Systems (DSS) have been proposed to assist drivers on the road by improving safety, efficiency and comfort in the driving experience. One important benefit of deploying such systems is that by aiding drivers in traversing traffic congestion on highways and consequently having vehicles moving more smoothly close to a constant speed, the emission of CO2 in the environment is reduced [Johannson 1999]. In the same context, a novel system referred to as the Congestion Assistant has been proposed in [van Driel 2007] by C.J.G. van Driel. In this work, a user needs survey conducted to investigate the perceived needs for driver assistance indicated high user acceptance, in particular, in receiving assistance with the driving task on congested roads. Based on user preferences, the Congestion Assistant has been designed and later evaluated by means of traffic simulation. The assessment of the system focused on traffic efficiency and safety and demonstrated reduction in congestion for all variants of Congestion Assistant considered. Nevertheless, some of its basic operations require information regarding the upcoming traffic condition on the road and no system to acquire it has been proposed. Given the advantage of rapid dissemination of traffic information by means of vehicular communication and the necessity for the Congestion Assistant to acquire information regarding the upcoming traffic, Martijn van Eenennaam has introduced in [van Eenennaam 2008] an efficient means to provide an over-the-horizon awareness of traffic jams ahead on the road to vehicles by means of multi-hop vehicle-to-vehicle communication. The proposed solution is a communication protocol that complies with information requirements derived from the Congestion Assistant. Nevertheless, this solution has been designed with one-dimensional straight highway scenarios in mind and extensions and/or adaptations might be necessary to make it solution adequate for more real-world scenarios. In this work, we present a networking solution, the Over-the-Horizon Awareness (OTHA) protocol, that altogether comprises extensions and modifications to the communication protocol presented in [van Eenennaam 2008] in order to address more realistic scenarios. In particular, the following Highway Real-World Scenarios are considered: single-lane roads, multiple-lane roads, junctions, and roads with multiple (opposite) directions. The performance of the OTHA protocol is evaluated by means of simulation. We assess the protocol both in a controlled environment with static scenarios and under a more realistic scenario consisting of vehicle traces with high mobility and speed variations. The results obtained indicate good performance of the protocol with respect to the metrics evaluated. In particular, the performance of the protocol in multiple-lane scenarios is found to deteriorate in high vehicle densities and possible solutions to overcome this problem are described.