In an autonomous vehicle level 3 and 4--which needs driver override in critical situations, multiple studies have been shown that drivers react with delay or inappropriately to the situations. This research aims, providing unconscious systematic input channel using subliminal stimuli to enhance situational awareness in critical situation and consequently minimizing road accidents. It is hypothesized: resulting from providing subliminal signals in advance to the supra-liminla ones, pre-conscious activation occurs unconsciousely which leads to enhance the time and precision of the reaction.