Over the last several years, the buzzword in the area of vehicle safety has been "active" safety. Blind-spot monitoring systems, stability control, night vision and many other high-tech solutions are now common in new vehicles. But Mercedes-Benz's latest advancement is an improvement on one of the most basic safety systems of all… the seat belt.
The new active seat belt is different from other seat belt systems because of its use of an electric motor in the buckle. The electric motor allows the buckle to extend upward about 2.8 inches from the seats when the rear doors are opened, making them more visible to rear passengers. Helping visibility even further is the buckle's illuminated insertion slot, which makes buckling-up in the dark especially easy for passengers, particularly for children. After the passengers strap in, the buckle retracts back to its original position, minimizing slack near the pelvis and thorax area while comfortably securing the passenger.
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. The buckle also branches off at a lower point at the occupant's hip to reduce the chance of the pelvis pushing through the belt. Should an accident happen, the seat belt buckles will extend upward when the rear doors are opened, but only if the vehicle is stationary, and of course, if the on-board electrical system is intact.
For such an advanced seat belt system, safety engineers had to use advanced dummies, as well. Virtual human models were used in place of the traditional crash dummies because they better simulated the impact to humans' internal organs, joints, bones, etc.
The new seat belt system is still under development, but Mercedes says it will debut in one of its upcoming models soon.