The door and frame connection of a car is a weak spot in side collisions. After detecting an impending impact via mounted cameras and radar sensors, the experimental German safety system sends out an electric charge to the shape-memory alloy on the door. The alloy expands from the heat, which serves to reinforce the door-frame bond. The researchers are currently testing prototypes and plan to start full test crashes with vehicles in 2008.
[Source: New Scientist Tech via Cars!Cars!Cars!]