Abstract
Eye closure rate (REC) is today considered as a convenient index in order to make the assessment of driver's vigilance degree at the wheel. The authors have recorded REC time variation for 12 subjects during a 2 hour driving period in real conditions, and carried out specific processes. They allow them to observe differences between subjects with descriptive and non parametric statistic processing. Differences are mainly due to the driving task and the performance failure. The authors also observed an unexpected kind of classification for drivers.