Researchers reported that the device can measure blood-alcohol levels from a distance of about 65 feet. The device works using a process known as standoff detection, in which the laser is bounced off of a mirror on the opposite side of the road, but if the beam is at all absorbed by alcohol vapor, the time difference is detected and the driver is busted.
The device has not yet been used on the roads or with moving vehicles, but was sensitive enough in lab trials to detect a blood-alcohol level of 0.1 percent. (.08 is the legal limit for driving in most states.)
