Abstract
We clarified the methodology for the evaluation of Situation Awareness (SA) while driving with low speed adaptive cruise control systems. It was shown that Time to Collision (TTC) is a useful index for indirect measuring methods (i.e, observing drivers' braking timing in terms of TTC) and the recognition level concerning the behaviour of surrounding vehicle is a useful index for direct measuring methods (i.e., the subjectively evaluating situational awareness). We also clarified that the indirect measuring method and the direct measuring method for evaluating SA were correlated. Specifically, the TTC derived from braking timing meaning the time margin to the collision becomes small when the drivers' awareness of surrounding vehicle is low.
