This paper focuses on the pilot study on Advanced Automatic Collision Notification (AACN) and Helicopter Emergency Medical Service (HEMS) systems in Japan. The pilot study was carried out in Chiba prefecture by the AACN Committee in affiliation with Emergency Medical Network of Helicopter and Hospital (HEM-Net).

There were many opinions that Japanese accident data was preferable to develop a Japanese AACN algorithm. Then, the Occupant Injury Predict Algorithm newly developed by Nihon University was utilized for the study. About 2.8 million Japanese accident data (so called ITARDA Macro Data) were used to define logistic regression risk curves of fatal and severe injuries to car occupants. To validate this algorithm, the in-depth accident case study by Nihon University and Nihon Medical University at the Chiba Hokusoh Hospital was used. Moreover, to decide the threshold value, this in-depth accident study was also used.

Regarding the AACN prototype system, HELPNET infrastructures already developed for existing Japanese ACN service were used for sending vehicle data to the HELPNET center. In the simulated accident, Event Data Recorder (EDR) data was added on usual HELPNET data and transmitted from a car to a HELPNET server at the HELPNET center. The AACN server got vehicle data such as Delta V and seatbelt status as input to the algorithm.

The result was transmitted to a Tablet PC at the Fire Department Head Quarters and Chiba Hokusoh hospital simultaneously. An operator of HELPNET made an Emergency Call to both the Fire Department and Hokusoh hospital individually.

In case of severe injury, a Tablet PC indicated the situation and a doctor dispatched to the accident spot by a helicopter. After a helicopter with a doctor took off, verbal communications between the helicopter and Fire Department started to decide a rendezvous point nearby the crash spot. After landing, the doctor contacted the injured occupant who was carried by an ambulance there. The AACN prototype system for a limited area, only in Chiba prefecture, was developed.

AACN transmitting tests were carried out at some spots in Chiba prefecture within the jurisdiction of two headquarters individually. The prototype AACN system operated as intended. Within a minute from the airbag deployment signal, the algorithm result screen arrived simultaneously on AACN Tablet PCs at Chiba Hokusoh hospital, Chiba prefecture Fire Department H.Q. and also at the transmitting spot. The next step of AACN transmitting test should be that AACN activates HEMS of Chiba Hokusoh hospital. To expand cover area in Japan, collaborations of other HEMS base hospitals in other prefectures should be planed soon.