It's a bad idea to drink and drive. No rocket science there. But with the goal of reducing drunken driving, researchers have gone high-tech, creating a laser device that can detect alcohol vapor within a moving car, from alongside the road. After the laser is shone through a speeding vehicle, a mirror bounces it back to a detector that can sense small concentrations of alcohol.
In the study, published in the Journal of Applied Remote Sensing, the researchers found that it could detect the amount of alcohol exhaled by a drunk person with a blood alcohol concentration above 0.1 percent. There were a number of assumptions that went into that calculation, but the researchers suggest that the device may be even more sensitive than stated, since the temperature of the human lung is higher than the device used in the experiment, and thus breath may contain more alcohol in the real world than modeled in the lab. (That said, the U.S. National Transportation Safety Board says you're drunk at 0.05 percent blood-alcohol content.)