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Next: Cars that know when to speak

Nuance Communications Inc. has taught our cars how to talk. Now it’s trying to teach them when to shut up.

Earlier this month, Burlington-based Nuance received a US patent for a system that reads incoming text messages aloud, through a car’s audio system — but only when it concludes that it’s safe for the driver to hear them.

A car can’t read minds, but its built-in sensors can read the road. The Nuance system captures data on driving conditions and uses it to decide whether it’s the best time to play incoming messages.

Nuance is a leading maker of software that translates spoken words into digital text, and text into speech. Its software is installed in smartphones, including the Apple Inc. iPhone, personal computers, and cars. The company’s Dragon Drive system lets drivers place calls or send texts using voice commands, or hear incoming messages read aloud.


Nuance declined to comment, but according to its patent, the technology would constantly monitor the car’s speed, traffic density, and road conditions, and also download weather data from the Internet. It uses this information to estimate the amount of conscious effort a driver needs to safely operate the car under certain conditions.

“While in some driving situations it may be dangerous to perform any extra tasks such as instant messaging, there also are situations when it can be relatively safe,” the patent reads.

The new system is designed to identify those relatively safe portions of a road trip.

For example, when driving conditions are less than intense — say, early morning during light traffic — the Nuance system would allow incoming messages to play immediately.

But as conditions became more challenging, it would delay releasing those messages.

For instance, suppose the car is changing lanes while accelerating. The Nuance system could conclude that the driver was passing another car and hold all incoming messages until the maneuver was completed.


It could even take into account the behavior of the driver and passengers. The Nuance patent includes features that would scan the driver’s face or note the tone of his voice, in order to detect signs of stress. It could also detect voices inside the vehicle, allowing it to judge whether the driver was being distracted by chatting with a passenger.

Bryan Reimer, a research scientist at the Massachusetts Institute of Technology, said the Nuance technology is the latest of many efforts to design automotive systems that adjust to the mental state of the driver.

For example, in 2003, Volvo introduced the Intelligent Driver Information System, which tracks the car’s speed, steering wheel position, and turn-signal settings to estimate the driver’s workload. Above a certain threshold, the Volvo system intercepts incoming cellphone calls, so the driver can concentrate on driving.

Reimer, cofounder of a research consortium that studies distracted driving, said that implementing the Nuance system will be difficult. “I’m not convinced how well they can do it, without seeing details,” he said.

But, Reimer added, “I’m convinced it’s conceptually feasible.”

But will it make cars safer?

Joel Cooper, research assistant professor of psychology at the University of Utah, said that using speech instead of pushbuttons or touchscreens does little to reduce driver distraction.

“When drivers engage in these kinds of speech dialogues,” Cooper said, “their momentary workload is significantly higher than we had previously anticipated.”


His research found that dialing a cellphone number with a voice command produces the same level of mental stress as doing arithmetic problems.

Cooper said that listening to incoming text messages is less distracting, but still requires more mental effort than simply driving.

Cooper said that no technical fix will completely cure distracted driving.

“There’s an infinite number of types of distractions out there,” he said, ranging from beautiful scenery to the driver’s own thoughts. But anything that keeps drivers focused on operating the vehicle is bound to improve highway safety, he added.

“It sounds to me like this technology has this potential,” he said.

Hiawatha Bray can be reached at hiawatha.bray@globe.com. Follow him on Twitter @GlobeTechLab.