German safety pioneer Mercedes-Benz will start fitting inflatable rear passenger seatbelts to its vehicles, in a move that will make the brand the second automaker to employ the safety technology behind Ford.

Mercedes says the 'Beltbag' is due to go into production in a luxury-class model, set to be the next-generation Mercedes-Benz S-Class as CarAdvice reported last month.

The seatbelt airbags are deployed when crash sensors detect a severe frontal impact, inflating the multi-layered belt strap to nearly three times its normal width. The larger surface area means better distribution of force, reducing the risk of injury to rear-seat passengers in a head-on collision by lessening the strain placed on the ribcage.

Mercedes is not planning to introduce the Beltbag for front seat occupants, citing the existing airbags and restraint systems already included in its cars.

Ford was the first manufacturer to introduce inflatable rear seatbelts. The seatbelt airbags are available in the 2011 Ford Explorer in North America and will be included as an option in the next-generation Ford Mondeo, due to reach showrooms in Europe next year. The Mondeo will make Ford the first manufacturer to offer seatbelt airbags in a mainstream car in Europe.

Car Advice