The impact of age on useful visual field deterioration and risk evaluation in a simulated driving task

The primary goal of this study is to evaluate whether the driver can estimate his performance and the deterioration of his state of alertness during a simulated driving task. The second goal is to study the relation between useful visual field (UVF) deterioration and the capacity to estimate performance in a visual task and the decrease of level of alertness as a function of age. In our experiment, two groups of subjects: 10 drivers between 21 and 34 years old and nine drivers between 46 and 57 years old were required to follow a vehicle in a simulated road traffic situation for 2 hours. In addition, the driver had to detect the change of colour of a signal located in the central part of his visual field or a peripheral signal appeared on the rear light of one of the vehicles in the traffic. The analysis of data collected during this visual task confirms that UVF deteriorates with the duration of the driving task and with the driver's age. The analysis of subjective data related to the state of alertness highlights an effect both of age and of the moment when this self-evaluation was carried out. However, self-evaluation of the subject's performance does not depend on driver's age. Finally, the study shows that the correlation between objective data (performance of visual task) and subjective data (state of drowsiness and self-evaluation of performance of the visual task) is low, and the implications with regard to road safety are discussed.