This report describes an experiment aimed at assessing the safety effects of in-vehicle information systems (IVISs) caused by overload and distraction of the driver. In the experiment, twelve subjects drove on urban and rural roads. The urban part contained three instances of four common driving situations: turning right, negotiating general regulation intersections, negotiating yield intersections, and driving straight ahead at major arteries. Safety in these situations was assessed by subjective ratings by a driving instructor, and by objective measurements. The results indicate that subjective ratings are more suitable for safety evaluation than objective measurements, and that programming a filter yielded eight times more unsafe driving situations than a control condition. Determining whether relevant congestion messages are provided by watching a map display or listening to speech messages also yielded three to four times the number of unsafe situations. A framework for developing safety guidelines is presented, safety and performance criteria are proposed, and ergonomic criteria are presented. Simple laboratory tests are described that might allow determining whether an IVIS is likely to affect safety due to overload and distraction. (A)
Abstract