In this paper, we propose a novel approach to recognize the awareness or the unawareness that a driver has of a pedestrian appearing on the road in front of the vehicle. Based on the theory of situation awareness and the collected driving data from the on board sensors, a suitable Hidden Markov Model (HMM) is used to model the "Driver Awareness of Pedestrian" and the "Driver Unawareness of Pedestrian". These behaviors are then recognized by using a maximum-likelihood decision method. A real-time validation taken on a driving simulator shows that the model and the output decisions are accurate and efficient.