The vehicle's motion detection with concurrent self motion is an important dynamic task concerning vehicle's collision avoidance. In this paper the authors present empirical data relating this task with environmental and individual factors such as (a) different kinds of road pavements (bituminous, concrete and bituminous pavement with chromatic bands); (b) several measures traditionally used in driver's assessment, e.g. vision parameters and reaction times; (c) age and sex of drivers. One hundred and six persons participated in this study. Using computer generated images with realistic textures, they simulated a situation where participants had to detect a vehicle's motion. All participants were also tested in several measures used traditionally in drivers' assessment such as vision and reaction time tests. The vehicle's motion detection was more impaired in the situation of a pavement with chromatic bands, which is the pavement with the higher optical flow density. These results showed that the optical flow played a more important role than the contrast between the object (vehicle) and the background (road) for visual motion detection tasks. Concerning the drivers assessment the authors point out the need of giving more importance to visual dynamic tests, contrast acuity and dazzling recovery time. Traditional tests of static visual acuity and reaction times should have less weight. Relatively to the sex and age variables the results showed that the relation between age and the vehicle's motion detection is different for females and males. Females give fewer errors than males, but with age increment they need more time to detect the vehicle's motion. Males need less time to detect a vehicle's motion but with age they give more errors than females. From an ecological point of view, both behaviours reveal a negative effect of age on the vehicle's motion detection because a wrong detection could be as dangerous a a slow detection. (A)
Abstract