•Operating conditions - Specifying the conditions under which the system must be operable, e.g. the DDAW system must be automatically activated at speeds above 70 km/h, the system must operate under both daytime and night time conditions, etc. •Performance criteria - Specifying the driver drowsiness level at which a warning must be given and giving examples of the criteria that can be used to assess driver drowsiness. •Driver warnings - Specifying the types and combinations of visual, audible and other warnings that are required/permissible.