Drivers are increasingly confronted with new sources of information like auditory instructions or warnings from In-Vehicle Information Systems (IVIS). In the near future many passenger cars will be equipped with automatic warning systems such as speeding and headway distance alerts.
This can overwhelm the driver due to the amount of information they must work with. Furthermore, in order to use the increasing capacity of roadside information better, complex traffic management systems have been developed by traffic engineers. These include variable traffic signs with changeable display panels and special marks and signals for safety. These contribute considerably to complexity of driving task and encroachment of attention. The analysis of accidents in several countries shows an increasing number of accidents partly due to the use and abuse of mobile phones, GPS-Systems and DVD displays in vehicles.
The main objective of the project is to estimate the influence of modern In-Vehicle Information Systems on road safety. A study of driver´s behaviour has been performed. Drivers have been selected according to defined demographic characteristics and the study has been performed under real traffic conditions.
20 younger (28 to 35 years old) and 20 elderly (60 to 65 years old) drivers have been studied. Depending on the test arrangement, subjects have been driving on selected road sections either with or without the support of IVIS while continuous speed profiles and critical driving situations have been recorded. A passenger car equipped with a route guidance system, standard FM radio and hands-free mobile phone was used as an experimental vehicle. The vehicle also contained toll sensors and data logging capability. Through comparison of test drives with and without support of IVIS, possible differences in speed behaviour, headway distance behaviour, and driver workload shall be observed and assessed with regard to possible effects on road safety. In the traffic-psychological research, the changes of workload have been ascertained and investigated. The external, independent experimental terms have to be excluded during the process of data collection, in order not to falsify the results. Within the research project an estimation of safety gains and safety deficits due to changes of individual driving behaviour caused by influences of In-Vehicle Information Systems (IVIS) should be done. The central question of this research project is to recognise and assess the combined influences of certain IVIS on road safety requirements.
The considered experiment shows as a consequence of using IVIS – regarding all subjects – only small differences in driving behaviour. No significant changes of speed values as a result of using IVIS were found by the analysis of the entire test track, neither at urban road nor at freeways. Certainly it has shown that at the determined changes differences between the two age groups exists. So the younger subjects belong to drives who are on the freeway supported by IVIS more often in comparison with the group of fast drivers (speed value V85%) whereas most of the elderly subjects belong to the group of slow drivers (speed value V15%). Surprisingly the driving behaviour for drives on the urban road shows converse tendencies. Here the elderly subjects mostly belong to the group of fast drivers when driving with support of IVIS. This behaviour belonged to the lack of knowledge in the traffic engineering report.
As expected differences between the test tracks according to the influence of IVIS(highway with high speed level / urban road with low speed level) exist. So the differences at the highway drive because of IVIS are ascertainable via speed values whereas at the urban road route the changes are noticeable because of the frequency of safety relevant events. The mentioned frequency of events at the urban road route reveals clearly differences between the two age groups. For the elderly participants the frequency of safety relevant events has considerably increased during the drives withIVIS, whereas the speed behaviour remained unchanged. This result was distinctive at the urban road section where IVIS was used and the mobile phone call was taking place. In contrast to this mentioned fact an increase of events wasn’t recognised among the younger subjects. At the freeway route the reverse results have been found. Here the frequency of safety relevant events has been clearly reduced for elderly participants when they have been driving with support of IVIS. It is known from traffic psychological research that elderly people can compensate deficits of capacity of reaction and level of attention because of their lifetime experience in road traffic (particularly the predictability of traffic situations). As the results show, the compensation ability has its limits.
A study following the effects of IVIS on road safety.
Results of the study may support the transport safety policy.