Preliminary experiments about following distance for obtaining benefit under some conditions

Saving energy is one of the hottest topics among the traffic problems. It is well-known that shortening distance between two vehicles reduces aero resistance of them and leads energy saving. Some projects, where tracks or vehicles travel in a platoon with short distance headway from the preceding vehicle by using automated driving system or driver assistance system, have been performed. It is clear that maintaining enough distance between two vehicles is necessary for safe driving. However, if V2V technology including automated driving system can be utilized, the necessary distance that a driver must maintain can be small. This study focuses on the benefit obtained by the short distance (close-following). There are some factors that affect the following distance. The objective of this study is to evaluate the relationships among the following distance, driver´s feature and some conditions when the driver would like to obtain the benefit from the short distance. The preliminary experimental study with real vehicles on the test track has been done as a first step of the experiments. Two main scenarios were arranged: one is that a subject drives the following vehicle; the other is that a subject sits on the front passenger seat on the following vehicle a staff drives. Two kinds of leading vehicles were used, and three and two kinds of distances in each scenario were measured in this experiment. Also, the well-known method for categorizing a driver was employed in this study. The experimental result shows the several tendencies about relationships between the category of subjects and amount of the benefit from the short distance, and we can utilize this result and tendency for further experiments with more subjects. Moreover, this tendency, which will be concluded with many subjects, can be available for penetration of eco-driving system.