Intelligent Cruise Control (ICC) systems are likely to be one of the first applications of Automatic Vehicle Guidance (AVG) systems that could become available in the near future. In addition to maintaining vehicle speed at a preset level (like the existing cruise control), ICC's also regulate headway and vehicle speed when following another vehicle in front. Headway is expressed as time headway (THW), which is the distance from bumper to bumper between the car and the lead vehicle divided by the speed (in m/s) of the following car. THW is constant within one individual driver. There are however large individual differences in preferred THW. The main point of research in this study is the magnitude of THW ICC's adopt and the THW individual car drivers would prefer when driving with an ICC. Drivers may have problems accepting an ICC system when the THW is not in accordance with their personally preferred THW. In the present experiment ICC's with three different THW's are tested in a driving simulator. Two of these THW's can be found in prototypes of ICC's that are described in the literature, 1.5 s. and 1.0 s. The third THW is the one that is personally preferred by the subjects. It is expected that the ICC system that adopts a THW equal or close to the preferred THW is most accepted by the subjects. (A)
Abstract