DEARBORN, MI - After launching its industry-first rear inflatable seat belts on the new Ford Explorer, Ford Motor Co. is now expanding availability to the Ford Flex and Lincoln vehicles set to arrive in dealer showrooms next summer.

"This advanced restraint system is designed to help reduce head, neck and chest injuries for rear seat passengers, often children and older passengers who can be more vulnerable to such injuries," said Sue Cischke, Ford group vice president of sustainability, environment and safety engineering.

The addition of the inflatable rear seat belts to Flex builds on the Top Safety Pick ratings the vehicle recently earned from the Insurance Institute for Highway Safety. Ford plans to continue offering the inflatable belts affordably after launching them on the new Explorer.

The inflatable belts were added this spring, bolstering Explorer's already extensive suite of safety innovations. The vehicle already has seen strong demand from customers for its safety and driver-assist technologies.

In everyday use, the inflatable belts operate like conventional seat belts and are compatible with child safety seats. In Ford's research, more than 90 percent of those who tested the inflatable belts found them to be similar to or more comfortable than a conventional belt because they feel padded and softer. That comfort factor could help improve the 61 percent rear belt usage in the U.S., which compares to 82 percent usage by front seat passengers, according to National Highway Traffic Safety Administration data.

In the event of a frontal or side crash, the inflated belt helps distribute crash force energy across five times more of the occupant's torso than a traditional belt. That expands its range of protection and helps reduce the risk of injury by diffusing crash pressure over a larger area, while providing additional support to the head and neck. After deployment, the belt remains inflated for several seconds before dispersing its air through the pores of the airbag.

Vehicle safety sensors determine the severity of the collision in the blink of an eye and deploy the inflatable belt's airbag. Each belt's tubular airbag inflates with cold compressed gas, which flows through a specially designed buckle from a cylinder housed below the seat.

The use of cold compressed gas instead of a heat-generating chemical reaction - which is typical of traditional airbag systems - means the inflated belts feel no warmer on the wearer's body than the ambient temperature. The inflatable belts also fill at a lower pressure and a slower rate than traditional airbags, because the device does not need to close a gap between the belt and the occupant. The inflatable belt's accordion-folded bag breaks through the belt fabric as it fills with air, expanding sideways across the occupant's body.

"It's a very simple and logical system, but it required extensive trial and error and testing over several years to prove out the technology and ensure precise, reliable performance in a crash situation," said Srini Sundararajan, safety technical leader for Ford Research and Innovation.