Abstract
Keywords: Inter-Vehicle-Communication, C2C, intersection assistance, HMI, ADAS, warning assistance
In this paper the development of an intersection assistance system is described, which is based on C2C. The objective of the system is to prevent accidents at intersections, which make in Europe about 35 % of all accidents.
The system, which will be presented in this paper, was previously implemented in a traffic flow simulator and a driving simulator, where the impact of the system on traffic safety has been analysed and in a first stage the user acceptance has been evaluated. In the simulator several HMI concepts have also been developed and evaluated by subjects. Also these results will be presented briefly in the paper.
The main focus of the paper is on the implementation of the system in real vehicles and the evaluation of the system by subjects on a real intersection.
An overview of the system architecture and the data communication of two test vehicles is given. In the test, a BMW 728iA is used as a host vehicle, which is equipped with the intersection assistance system, GPS receiver and communication device. A MB A170 is used as the foreign vehicle. In the foreign vehicle information on the position and driving state is gathered from different sensors and broadcasted by a microcontroller via a WLAN-device.
The host vehicle receives this information and process it in order to assess the traffic situation. Based on a digital map of the intersection, which includes relevant information like intersection layout, right of way regulation etc., and the gathered information about the driving state of both vehicles, a risk assessment of the current situation is done by anticipating the future traffic situation at the intersection. In case of identified critical situations the driver is informed and warned, which gives him the possibility for an early intervention to prevent an accident.
Three HMI concepts were chosen for the subject tests based on the results, which were achieved in the driving simulator study: head-up display (HUD) in combination with centre console display (CCD), a display in the instrument cluster (IPD) and a combination with an acoustic (verbal) warning and CCD.
With these vehicles test were conducted on a real intersection with subjects of different age, gender and driving experience. Different intersection scenarios were driven by the subjects in form of a screenplay. After each scenario the subjects filled out a questionnaire. The scenarios included also intersection situations with occluded side traffic or occluded oncoming traffic at left turn.
Based on the stored data an the questionnaires aspects like the system performance, the user acceptance, the influence of the intersection assistant on driving behaviour, the usability of the HMI etc. were analysed and evaluated. The innovative aspect of this approach is that it uses only C2C without any other additional environmental sensors. Also no sophisticated technology but simple and available technology (WLAN, pure GPS etc.) is utilised. The evaluation of the system with subjects proved the feasibility of such a systems. The user acceptance was quite high.