An Event-Driven Cooperative Advanced Driver Assistance System to Mitigate Vehicular Traffic Shock Waves in Temporarily High Traffic Demand

Doctoral thesis (2015)

In uncoordinated vehicular traffic, available road capacity cannot be fully exploited. This often leads to the formation of traffic jams and the emergence of vehicular traffic shock waves in times of ... [more ▼]

In uncoordinated vehicular traffic, available road capacity cannot be fully exploited. This often leads to the formation of traffic jams and the emergence of vehicular traffic shock waves in times of temporarily high traffic demand. The main reason for congestion on highways is the combination of high traffic demand and small instabilities in the flow. These can be caused by bottleneck situations such as ramps, construction sites, accidents, or by small inaccuracies of human drivers. Traffic jams that are caused by the latter reason often are referred to as phantom jams. Even with modern vehicles, equipped with several sensors and driver supporting features, the drivers’ or sensors’ line of sight are already limited by the vehicle ahead. Hence, drivers or vehicles are not able to take anticipatory actions. To overcome these limitations it is necessary to investigate cooperative systems that are connected through a communication channel. In this work, we introduce a novel distributed, connectionless and event-based communication protocol that enables us to eliminate up- stream shock wave formation already with low system penetration rates. Based on traffic information ahead, we propose a Cooperative Advanced Driver Assistance System (CADAS) that recommends pre-emptive velocity reductions in order to redistribute traffic more uniformly thereby eliminating traffic peaks. Simulation results show that our proposed CADAS increases and harmonizes the average velocity, and therewith reduces the overall travel time, avoiding unnecessary slowdowns. We also demonstrate that our event-based messaging scheme uses less network resources than beaconing. Moreover, we conduct a field test on a private test track in order to validate our proposed protocol. We compare uncoordinated traffic to traffic, controlled by the proposed CADAS. With our experiments, we show that such a recommendation-based system can alleviate the formation of vehicular shock waves, thus improve vehicular traffic. Additionally, we perform simulations on the experiment scenario and compare the results to the empirical ones. With this comparison we show that our simulation results agree with the findings from the field test. [less ▲]

An Event-Driven Inter-Vehicle Communication Protocol to Attenuate Vehicular Shock Waves

in International Conference on Connected Vehicles and Expo (2014, November)

In this paper we investigate an event-driven Inter-Vehicle Communication protocol to mitigate shock waves in dense traffic situation. From previous work we know that flooding or frequent beaconing require ... [more ▼]

In this paper we investigate an event-driven Inter-Vehicle Communication protocol to mitigate shock waves in dense traffic situation. From previous work we know that flooding or frequent beaconing require excessive network resources. To overcome this limitation we focus on an efficient message exchange mechanism requiring as few network resources as possible, while still providing timely and accurate traffic information. We designed Density Redistribution through Intelligent Velocity Estimation (DRIVE), an event-driven Inter-Vehicle Communication protocol that learns about traffic conditions ahead and recommends optimal velocities in order to prevent the formation of vehicular shock waves. We demonstrate that our approach of reacting in case of traffic fluctuations leads to significant improvements in overall traffic flow. Furthermore we show that even a low number of equipped vehicles is sufficient to achieve this target. [less ▲]

A Cooperative Advanced Driver Assistance System to Mitigate Vehicular Traffic Shock Waves

in IEEE INFOCOM 2014 - IEEE Conference on Computer Communications (2014)

We address the problem of shock wave formation in uncoordinated highway traffic. First, we identify the combination of heavy traffic and small traffic perturbations or unexpected driver actions as the ... [more ▼]

We address the problem of shock wave formation in uncoordinated highway traffic. First, we identify the combination of heavy traffic and small traffic perturbations or unexpected driver actions as the main causes of highway traffic jams. Then we introduce a novel distributed communication protocol that enables us to eliminate upstream shock wave formation even with low system penetration rates. Based on traffic information ahead, we propose a Cooperative Advanced Driver Assistance System (CADAS) that recommends non-intuitive velocity reductions in order to redistribute traffic more uniformly thereby eliminating traffic peaks. Simulation results show that CADAS significantly increases the average velocity and therewith reduces the overall travel time and avoids unnecessary slowdowns. [less ▲]

Evaluation of Sensors in Modern Smartphones for Vehicular Traffic Monitoring

Report (2012)

Improving Highway Traffic through Partial Velocity Synchronization

in Proceedings of the IEEE Global Communications Conference 2012 (2012)

In this paper we address the problem of uncoor- dinated highway traffic. We first identify the main causes of the capacity drop, namely high traffic demand and inadequate driver reaction. In the past ... [more ▼]

In this paper we address the problem of uncoor- dinated highway traffic. We first identify the main causes of the capacity drop, namely high traffic demand and inadequate driver reaction. In the past, traffic and user behavior have been accurately described by cellular automata (CA) models. In this paper we extend the CA model to deal with highway traffic fluctuations and jams. Specifically, the model incorporates the communication layer between vehicles. The model thus enables us to study the impact of inter-vehicular communications and in particular the delivery of critical and timely upstream traffic information on driver reaction. Based on the newly-available traffic metrics, we propose an Advanced Driver Assistance System (ADAS) that suggests non-intuitive speed reduction in order to avoid the formation of so-called phantom jams. The results show that using such a system considerably increases the overall traffic flow, reduces travel time and avoids unnecessary slow-downs. [less ▲]