This unusual-looking gadget is worn behind the ear, and wakes you up if you start to catch some Z's on the highway. It constantly measures the angle your head is resting at, and vibrates if you tip forward. Of course, if you fall asleep and lean back into your headrest, then it will happily let you careen off the road to your fiery, but restful, death.
The design comes from Korean company Design Fingers but there's no word on availability. Popgadget helpfully point us to a similar product on Amazon though, if you really must get your hands on something like this. [Popgadget]