The introduction of advanced driver information systems may affect the driver's ability to control the vehicle safely. These systems must be evaluated to ascertain that they do not impose an unreasonable demand on the driver. This paper discusses a practical experiment to evaluate the use of driver information systems on observable driver behaviour, while driving on the road. An investigation was made into the visual demands and subjective mental workload resulting from the use of a congestion warning device, an in-car entertainment system and normal driving. Video tape was used to record the driver's visual behaviour. This was then analysed to calculate glance frequency, glance duration, eyes off-road time and percentage time off away from the forward view. NASA R-TLX was employed to determine subjective mental workload. The results of the study suggest that the measures employed detected a significantly greater visual demand and subjective mental workload imposed by the driver information system than by either the in-car entertainment system or the control condition. However, the difficulties in comparing such a study with other reported work are highlighted.
Abstract