The brainchild of Michael Graf at BMW and Michael Strolz's team at the Technical University of Munich, the "haptic" – technology that gives tactile feedback – doors could cut both road injuries and repair bills, they say.
The current prototype looks like a normal car door, but an extra metal bar runs through its centre and connects to the car's frame between the hinges. In normal mode, the bar moves freely and doesn't affect the door's movement.
However, if sensors detect a nearby obstacle at the same time as an accelerometer detects an attempt to open the door, the door's swing is restricted by a linear motor attached to the bar.