Abstract
A speculative exposition of human factors problems which accompany semiautomation of highway vehicles is presented. The problems are emphasised of manual control take-over from an automatic system under both normal and emergency conditions. A new way to consider driver alertness in terms of stability margins of control theory is hypothesised. A 3-time scale model of driver decision- making is proposed and two simulation techniques especially applicable to study driver alertness and manual control take-over are suggested. (Author/publisher)