Berthelon, C., INRETS, France
The driver's self-motion through a rigid environment generates lawful transformations of the optic array which have been called optical flow. The optical flow includes information about the driver's self-motion and about the structure of the environment in which the motion is occurring. These information are known to be used by the driver for controlling his trajectory and speed. Here, some driving simulation were carried out to specify the role of environmental cues in self-speed estimation. We varied road characteristics as : presence or absence of road markings, uniform or textured road surface, presence or absence of another vehicle. Participants had to evaluate their own self-speed. Results show that the enrichment of the road surface by road markings and road texture modifies the subjects' sensation of self-motion. However, the presence of another vehicle in the driver's field of view has also an effect on these estimation. Thus, global optic flow due to the driver's displacement but also local optical flow due to the presence of another vehicle could have a role in self-speed estimation.