A test service was launched Monday to dispatch ambulance helicopters to the scene of car accidents after analyzing data sent automatically from the vehicles, operators said.

Toyota Motor Corp. and Honda Motor Co. are teaming up with a nonprofit organization to test the feasibility of the service, called D-Call Net, with the aim of seeing it fully operational by 2018.

When air bags are deployed in a car accident, data such as the location and the severity of the crash, and whether the driver and passengers were wearing seatbelts, will be sent automatically to an operation center.

There, the data will be processed to estimate the probability of death and serious injury, based on a database on some 2.8 million car accidents in Japan, according to the Emergency Medical Network of Helicopters and Hospitals, a nonprofit organization.

Nine hospitals participating in the project will receive the information and dispatch ambulance helicopters as appropriate.

Although the number of traffic accident fatalities in Japan has been on the decline in recent years, more than 4,000 people were killed in 2014.

"We are trying to shorten the time between an accident and the start of medical treatment as much as possible because it makes a difference," said Kunihiro Mashiko, director of the Emergency Medical Network of Helicopters and Hospitals.

At present, only certain types of Toyota and Honda models, such as the Toyota Land Cruiser and Crown, and some Lexus models, are compatible, but organizers hope to increase the number of vehicles that support D-Call Net to around 400,000 by 2017.

Toyota Senior Managing Officer Moritaka Yoshida said the automaker hopes to get "actively involved" in the project, expressing hope of expanding the scope of cars targeted in the future.