The Qinetiq research company is developing sensor-based technology that measures drivers' blood alcohol levels. This new system is being funded by the National Highway Traffic Safety Administration and the Automotive Coalition for Traffic Safety. The sensors would automatically be built into the vehicle's steering wheel and be invisible on the car's interior.
As soon as the driver touches the sensor-based technology, you'll attain results on blood alcohol levels in about one second. The technology will only be released once it is absolutely accurate.