The Ford system operates by placing a small cylinder of cold compressed gas that sits underneath the rear seats, with an inflatable bag located in the seatbelts.  After a vehicle impact occurs, this new system is designed to spread the force of impact over more parts of the human body, which helps reduce the amount of impact felt by the human chest.

Although airbags are now common safety devices in all modern vehicles, Ford is poised to become the first automaker to introduce the inflatable rear seatbelts -- they'll launch next fall, when the 2011 Explorer is made available.

"It's hard to know for sure ahead of time, but this airbag has tremendous benefit by increasing the surface area (of the seat belt), and that allows them to restrain the torso better on a frail body," University of Michigan trauma surgeon Dr. Stewart Wang told The Detroit News.  "I think that the potential benefits are quite substantial."

As automakers look for new ways to attract car buyers, Ford has been quick to introduce in-car technology and additional features unavailable in some baseline and midrange vehicles from competing companies.

The new optional safety device will eventually be available for all Ford vehicles, but will have an additional cost auto buyers must pay.