New tech blocks texting from driver's seat

Using a vehicle's existing Bluetooth and audio technology, researchers have figured out how to block smartphone use by people behind the wheel, while passengers can text, talk, and tweet away.

Distracted driving is being tackled by state legislators, mobile carriers, and auto manufacturers with a disjointed collection of laws, apps, and hands-free technology. But wouldn't it be a lot easier if smartphones can tell when the their owner is behind the wheel of a car and just shut down all the tempting features?

Mobile operators such as Sprint and T-Mobileare employing technology to do something similar, but the antidistracted-driving apps lock down phones even if the user is a passenger or on public transportation. For that reason, the apps contain easy-to-use override buttons. But researchers at Stevens Institute of Technology and Rutgers in New Jersey are developing technology that can tell the difference and limit the driver's phone, while not interrupting service for occupants.

Current anti-distracted driving technology uses an app that runs in memory and uses the phone's GPS to figure out if a user is in a vehicle or not. This means that if a user is in a bus, taxi, or passenger seat, the phone locks up, and its effectiveness also depends on the phone's signal strength. However, an alternative strategy developed by a team led by Dr. Chen at Stevens and Drs. Marco Gruteser and Richard Martin of Rutgers University leverages a vehicle's Bluetooth technology and speakers to measure acoustically whether a phone is being used by someone behind the wheel or a passenger.

Using this strategy, a car stereo would generate a series of high-frequency signals that the smartphone would record and time how long it took the signal to reach the device to gauge the distance from each of the vehicle's speakers. By measuring the phone's distance between the speakers, the phone can estimate its distance from the car's center, and determine more than 95 percent of the time if the phone is in the possession of the driver or a passenger. Once the ownership is determined, the phone can figure out if it needs to lock down services.

Of course, this protocol has some limitations. It assumes that the driver will be in a vehicle equipped with Bluetooth and that all speakers are working. And it also assumes that users have paired their phones with the car's Bluetooth phone system. The data presented by researchers reports up to 95 percent accuracy (depending on wind noise, conversation, and background noise) in determining the phone's position in the car. But when the phones are placed in the cupholder--a favorite phone storage place of both the driver and the passenger--the algorithm accuracy drops down to 80 percent. It is still a lot more accurate than just figuring out if you're traveling at a rate of more than 5 mph.

Once the phone can tell if the user is behind the wheel, it could lock the phone's interface, or block texts and incoming calls altogether. It's not perfect, but it's closing in on taking the temptation to text out of the driver's hands, while not impeding the convenience of passengers.