A Florida man, 54-year-old Dennis Bellehumeur, has spent 12-years developing a sensor that can test blood alcohol content though a person's skin. When installed on the steering wheel, it would prevent a vehicle from being started if a driver is over the legal limit. He decided to invent this sensor when his teenage son suffered minor brain damage after he drove a car into a utility pole. Alcohol was a major factor in his son's accident. There are numerous obstacles to getting this sensor installed across the board. First of all, the legal level of blood alcohol content varies from state to state. Secondly, manufacturers would all have to install this device and integrate it in with their current ignition systems. There is, however, a chance this could be marketed as an aftermarket addition for law enforcement. If you install this on someone's car who is an offender, then it would prevent repeat offenses.