Worldwide, 1.2 million people die in road crashes yearly; 43,000 in Europe alone. This implies a cost to European society of approximately 160 billion euros, and takes up 10% of all healthcare resources. To reduce these rates, safety technologies have been developed which help to minimize the severity of injuries to vehicle occupants. However, studies have shown that most deaths due to road accidents occur in the time between the accident and the arrival of medical care. Therefore, a fast and efficient rescue operation would significantly increase the injured person's probability of survival.The aim of this project was to define the On-Board Unit (OBU) hardware and software installed in all modern vehicles which could request medical and technical support after a road accident. This device, based on the information from the vehicle sensors, automatically decides whether the car has suffered a road accident or not, the severity of the accident and the kind of accident (impact area).Two kinds of communications were set up in parallel: the first one was an automatic call between the Service Answering Point and the vehicle and the another was the sending of a text message in order to give more detailed information about aspects related to the accident configuration, the vehicle and occupants' state after the impact, the road features and the weather conditions at the site of the accident.Apart from the design of this system, a protocol to test this kind of device was defined. This procedure is based on the accelerations and the rotation suffered by the vehicle due to the collision.Besides providing the accident location, the value of this system compared to other eCall devices is a greater amount of information which allows emergency services to arrive in less time with the suitable tools to properly treat the injured.