Mercedes-Benz is developing a new type of active seatbelt buckle, which the automaker says will connect with its Pre-Safe crash avoidance system and will protect users better in the event of a crash. Mercedes hasn’t announced which models will receive it, since the feature is still in development, reports Kelley Blue Book.

This new rear-seat belt buckle has an electric motor that will extend the buckle 2.8 inches when the rear doors are opened, in order to make them easier to see and reach. Plus, the buckle’s insertion slot will light up, making it easier to see in the dark. Then, when clicked shut, the buckle will recede back to its lower starting point to tighten the belt further.

“The active seatbelt buckle is designed to reduce the belt slack in the area of the pelvis and thorax,” writes Inside Line. “The automaker said passengers are ‘secured more firmly in sideways and lengthways directions’ with the active seatbelt buckle.”

The seatbelt is also integrated with Mercedes’ other safety systems. “As part of Mercedes’ Pre-Safe crash avoidance system, when the risk of an accident is recognized, the belt buckle retracts about 1.6 inches, increasing belt-tensioning on passengers by up to 3 inches to better protect them in an accident,” reports Automobile Magazine. The seatbelts will release when the vehicle comes to a stop and the rear doors are opened.

Though Mercedes-Benz hasn’t mentioned which model will be the first to get this safety feature, it’s likely that its luxury sedans will be the first to offer it. That was the case with Mercedes’ Attention Assist drowsiness alert feature, which was first available on the redesigned 2010 E-Class.

Fortunately for shoppers who don’t have a Mercedes-Benz budget, many of Mercedes’ innovative safety features have filtered down to more affordable vehicles. As we reported earlier, the 2013 Mitsubishi Outlander will offer features like lane-keeping assist and adaptive cruise control, which are typically available in luxury vehicles, like the Infiniti FX. So if you like this feature, the next time you’re ready to buy a new car, it’s likely to be available in something a little cheaper than a flagship Mercedes-Benz sedan.

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