By Jil McIntosh

There are public service campaigns, there are companies that take your car home from the bar, there are stiff fines and vehicle seizures, and yet people still regularly drink too much and then get behind the wheel. Impaired driving remains a serious problem because it’s very difficult to stop drivers from getting into their cars, and many are caught only after the damage has been done.

A group of U.S. researchers is working on a possible solution, called DADSS, or Driver Alcohol Detection System for Safety. It’s a cooperative project by the National Highway Traffic Safety Administration (NHTSA) and the Automotive Coalition for Traffic Safety (ACTS), which works with the Alliance of Automobile Manufacturers. The five-year project comes with a US$10 million price tag that is shared between NHTSA and ACTS.

The goal of the DADSS program is to research, develop and demonstrate passive, non-invasive methods that quickly measure the driver’s BAC, or blood alcohol concentration, each time the driver gets into the vehicle. If the system detects a BAC at or above the U.S. legal limit of .08, the vehicle won’t start. It’s a very ambitious project, and the researchers are hoping to demonstrate a system on a research vehicle by 2013.

“There are tremendous challenges and most have to do with how complex a vehicle is itself,” said Wade Newton, director of communications for the Alliance of Automobile Manufacturers. “It’s 3,000 parts working together in all temperature conditions, whether it’s raining in Washington State or sunny in Florida, whether filled with passengers or empty, or maybe not even maintained. The device and technology must work all the time. A false reading in just a few of them would have a tremendous effect, because there are so many ‘traffic starts’ each year.”

Currently the researchers are looking at two possible technologies. One is tissue spectrometry, a touch-based approach that would probably be integrated into the vehicle’s starter button. An infrared light shining on the driver’s skin scatters several millimeters through it. As the light returns to the touch pad, it gathers information on the tissue’s chemical properties, which are analyzed to determine the alcohol concentration in it. The other is distant spectrometry, which assesses the alcohol concentration in the driver’s exhaled breath.

Compounding the difficulty for researchers is that the system must work very quickly, and be virtually invisible to the driver. It’s likely that a successful DADSS system would be included on all new vehicles, possibly mandated as a safety item just as anti-lock brakes or electronic stability control. That means it can’t be like an ignition interlock, which is often mandated by the courts for convicted drunk drivers, and which requires the driver to blow into the device each time the car is started. Since many people don’t drink any alcohol, a mandated system must be passive and not require them to take any action.