Most of the researchers and designers of WSN-based parking management system used wireless sensors to detect the car presence in automating the parking system. However, the problem of car-to-car collisions in the parking system was not discussed by these researches where the position details of cars are important to analyze the collision event. This paper presents the ubiquitous parking management system (UPMS) where the sensors are used to detect car presence and designed in multi-agent system to disseminate efficiently the information through the system. The proposed system uses a location technique based on RSS which is processed in multi-lateration method to know the position details of the cars. Also, the car active RFID (CARFID) is equipped with vibration sensors to detect the car collision event. The system verifies the collision event in the proposed oriented bounded box (OBB) intersection test. Experiment shows that the collision detection is more accurate if more wireless sensors are used in our proposed technique.