Integration of driver support functions: the driver's point of view

Integration of driver support functions is a key issue in the development of in-vehicle systems that assist the driver with the driving task. This paper discusses a user needs survey that provides more insight into this issue from the perspective of the driver. Car drivers are asked to indicate their needs for driver assistance during certain driving tasks (e.g. congestion driving) and circumstances (e.g. reduced visibility). From this, consequences for the integration of functions can be deduced with respect to technology, HMI and functional operation. Preliminary results of a pilot test of the user needs survey are highlighted in this paper. These results indicate starting points for integrated driver assistance, such as the adaptability of systems based on personal needs for support, and the functional integration of driver support functions, for instance with respect to inter-vehicle communication

Discrete time analysis of a slotted transmission system

This paper concerns the performance analysis of a slotted transmission system. Packets of equal size arrive at the transmission facility which can handle a certain maximum number of packets per time-unit called frame. Transmission is assumed to be gated at the start of frames. Temporary overflow is stored in a buffer with infinite capacity. The packet arrival process is described by a Markov chain with finite state space. We derive the stationary expected number of packets in the buffer and the stationary expected packet delay. We also formulate and describe the implementation of an algorithm to compute these quantities. The accuracy of the algorithm is checked by simulation. A realistic traffic model is given and specific parameters are chosen. Results and numerical aspects are evaluated

Analysis of a queuing model for slotted ring networks

We study a multi-server multi-queue system which is intended to model a local area network with slotted ring protocol. Two special cases of the model are analysed and the results are used to motivate an approach to approximate mean queue lengths in the general model

Traffic flow Impacts of a congestion assistant

This paper presents the results from a microscopic traffic simulation study that was conducted to investigate the impacts of a so-called Congestion Assistant on traffic efficiency and traffic safety. The Congestion Assistant is an in-vehicle system that supports the driver with an Active pedal when approaching a traffic jam and a Stop & Go when driving in a traffic jam. Six variants of the Congestion Assistant with different equipment rates on a four-lane highway with a lane drop were assessed. The traffic simulation tool was calibrated and validated using measured loop data on a segment of the Dutch A12 highway. The Congestion Assistant was found to reduce the amount of congestion significantly, especially due to the Stop & Go. This function led to more efficient car-following behavior by adapting smaller headways and eliminating the reaction time of drivers. The Active pedal of the Congestion Assistant hardly influenced traffic efficiency; rather it affected traffic safety through a safer approach to a jam

Investigation of user needs for driver assistance

Advanced Driver Assistance Systems (ADAS) aim at supporting the driver with the driving task and are expected to lead to a safer, cleaner and more efficient and comfortable transport system. This paper presents the results of an Internet questionnaire among more than 1000 Dutch car drivers. Respondents indicated their needs for driver assistance with certain driving tasks and situations. It appeared that warnings for downstream traffic conditions and traffic in blind spots were favoured. Apparently, the needs for warnings for downstream traffic conditions on motorways significantly differed from the needs for other driver support functions. Moreover, drivers preferred the ideal system to help them with critical situations (i.e. imminent crash and reduced visibility) and car following on motorways to other driving tasks and situations. Characteristics of the driver, system and traffic scene affected the needs for driver support. Besides, these needs indicated consequences for the integration of driver assistance. Driver support functions should exchange information to extend their individual fields of activity, for example by inter-vehicle communication (e.g. warning for downstream traffic conditions) or sensor data fusion (e.g. warning for an imminent crash)

Mobiliteit, mens en techniek

De mobiliteit van personen en goederen is onmisbaar binnen ons dagelijks leven en maatschappij. In Nederland nemen 7 miljoen personenauto’s ruim 80% van onze verplaatsingen voor hun rekening. Zo’n 60% van de goederen wordt over de weg vervoerd en 30% over het water. Berekeningen van het ministerie van Verkeer en Waterstaat voorspellen een toename van 20% van het personenvervoer en tot 80% van het goederenvervoer tussen 2000 en 2020

Modelling supported driving as an optimal control cycle: Framework and model characteristics

Driver assistance systems support drivers in operating vehicles in a safe, comfortable and efficient way, and thus may induce changes in traffic flow characteristics. This paper puts forward a receding horizon control framework to model driver assistance and cooperative systems. The accelerations of automated vehicles are controlled to optimise a cost function, assuming other vehicles driving at stationary conditions over a prediction horizon. The flexibility of the framework is demonstrated with controller design of Adaptive Cruise Control (ACC) and Cooperative ACC (C-ACC) systems. The proposed ACC and C-ACC model characteristics are investigated analytically, with focus on equilibrium solutions and stability properties. The proposed ACC model produces plausible human car-following behaviour and is unconditionally locally stable. By careful tuning of parameters, the ACC model generates similar stability characteristics as human driver models. The proposed C-ACC model results in convective downstream and absolute string instability, but not convective upstream string instability observed in human-driven traffic and in the ACC model. The control framework and analytical results provide insights into the influences of ACC and C-ACC systems on traffic flow operations.Comment: Submitted to Transportation Research Part C: Emerging Technologie

Effect of eHMI on pedestrian road crossing behavior in shared space with Automated Vehicles-A Virtual Reality study

A shared space area is a low-speed urban area in which pedestrians, cyclists, and vehicles share the road, often relying on informal interaction rules and greatly expanding freedom of movement for pedestrians and cyclists. While shared space has the potential to improve pedestrian priority in urban areas, it presents unique challenges for pedestrian-AV interaction due to the absence of a clear right of way. The current study applied Virtual Reality (VR) experiments to investigate pedestrian-AV interaction in a shared space, with a particular focus on the impact of external human-machine interfaces (eHMIs) on pedestrian crossing behavior. Fifty-three participants took part in the VR experiment and three eHMI conditions were investigated: no eHMI, eHMI with a pedestrian sign on the windshield, and eHMI with a projected zebra crossing on the road. Data collected via VR and questionnaires were used for objective and subjective measures to understand pedestrian-AV interaction. The study revealed that the presence of eHMI had an impact on participants' gazing behavior but not on their crossing decisions. Additionally, participants had a positive user experience with the current VR setting and expressed a high level of trust and perceived safety during their interaction with the AV. These findings highlight the potential of utilizing VR to explore and understand pedestrian-AV interactions

What impressions do users have after a ride in an automated shuttle? An interview study

In the future, automated shuttles may provide on-demand transport and serve as feeders to public transport systems. However, automated shuttles will only become widely used if they are accepted by the public. This paper presents results of an interview study with 30 users of an automated shuttle on the EUREF (Europäisches Energieforum) campus in Berlin-Schöneberg to obtain in-depth understanding of the acceptance of automated shuttles as feeders to public transport systems. From the interviews, we identified 340 quotes, which were classified into six categories: (1) expectations about the capabilities of the automated shuttle (10% of quotes), (2) evaluation of the shuttle performance (10%), (3) service quality (34%), (4) risk and benefit perception (15%), (5) travel purpose (25%), and (6) trust (6%). The quotes indicated that respondents had idealized expectations about the technological capabilities of the automated shuttle, which may have been fostered by the media. Respondents were positive about the idea of using automated shuttles as feeders to public transport systems but did not believe that the shuttle will allow them to engage in cognitively demanding activities such as working. Furthermore, 20% of respondents indicated to prefer supervision of shuttles via an external control room or steward on board over unsupervised automation. In conclusion, even though the current automated shuttle did not live up to the respondents’ expectations, respondents still perceived automated shuttles as a viable option for feeders to public transport systems.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Transport and PlanningHuman-Robot InteractionIntelligent VehiclesTransport and Plannin

Over-the-Horizon Awareness for Advanced Driver Assistance Systems: the TrafficFilter and microSlotted 1-Persistence Flooding

Vehicle-to-vehicle communications (V2V) is a promising technique for Advanced Driver Assistance Systems to increase traffic safety and efficiency. A proposed system is the Congestion Assistant, which supports drivers when approaching and driving in traffic congestion. Studies have shown great potential for such systems to reduce the impact of congestion, even at low penetration. However, these studies assumed complete and instantaneous knowledge regarding position and velocity of vehicles ahead. This paper refines and analyses the TrafficFilter, designed to supply the required information to the Congestion Assistant. Vehicles collaboratively build a so-called TrafficMap, providing over-the-horizon awareness. To this end, an improvement to the Slotted 1-Persistence Flooding called microSlotted 1-Persistence Flooding is proposed and evaluated. In a simulation study the TrafficFilter is found to be a viable system to build over-the-horizon awareness for future Advanced Driver Assistance Systems like the Congestion Assistant, without triggering the phenomenon known as Broadcast Storm