Due to demographic change, more elderly people have the need to preserve and support mobility by car despite age-related functional limitations. Since accidents by the elderly are primarily caused by age related limitations, and not by careless or irresponsible behavior, it may be beneficial to detect driving impairing conditions. The presented review gives an overview of technologies to detect driving impairing conditions like drowsiness and stress or excessive demand. A comparison of the approaches to detect these conditions suggests that a combination of approaches is the most feasible method. However, there are still few systems that focus on the elderly.