Mercedes-Benz to introduce inflatable seat belts

Mercedes' BeltBag system packs inflatable bags into a car's seat belts to distribute impact forces.

Soon, the inside of your car might be one big airbag. New cars have so many of these safety devices (the 2013 Dodge Dart has 10) that car makers may run out of places to put them. With a new systems called BeltBag, Mercedes-Benz will be putting them in the seat belts of a future luxury vehicle.

BeltBag is exactly what it sounds like. Cars equipped with the system will have an airbag embedded between the fabric layers of the seat belt. In a crash, a gas generator will inflate the bag within the belt, causing the belt itself to inflate. The belts use gas instead of the pyrotechnics in normal airbags to keep passengers from getting burned. This is why BeltBag is being called an “inflatable seat belt,” not an airbag.

Inflation will increase the surface area of the seat belt, which should distribute the force of an impact more evenly and decrease the chance of injuries from a body pulling against the belt.

The BeltBag will only be installed on rear seat belts. Mercedes says front passengers already have conventional airbags to soften the impact. Mercedes previewed BeltBag on the ESF 2009 concept, a modified current generation S-Class with added safety features. The German company did not say which production car will be the first to get BeltBag, but the next generation S-Class, due in 2013, is a good bet. The big Benz has traditionally been a showcase for the company’s new technologies; automotive journalists like to say that the features on a new S-Class will be standard equipment on cars 20 years from now.

This time, though, Mercedes was not the first. Ford launched an inflatable seat belt system on the 2011 Explorer, and may sell the system on other vehicles as well. It will be interesting to see what affect BeltBag will have in an actual crash. The Explorer received a four-star overall rating from the National Highway Traffic Safety Administration, and scored well in Insurance Institute for Highway Safety tests. However, there are many more factors at work than just seat belts.

With inflatable seat belts, the quest to protect passengers from 100 percent of accidents continues. To do this, cars of the future may be carrying a surprising amount of explosives and compressed gas. Who knows where airbags will turn up next?