Safer Driving with Speech

A new study by the Technical University of Braunschweig in Germany revealed significant benefits when drivers used their voices to select music, input addresses into navigation systems, and dial the phone while driving.

The 2008 In-Car Distraction Study, which was sponsored by Nuance Communications, exposed 30 drivers to a range of driving skills assessments, challenging each to drive while performing common tasks within the car. The test simulated driving and changing lanes while simultaneously selecting music on an MP3 player, making phone calls, and setting the address on a satellite-based navigation system. The test included objective measurements of each drivers' abilities to maintain a steady course and perform smooth and safe lane changes, and also measured their eye movements and awareness of their driving safety zone.

Authors of the study concluded that speech-recognition significantly reduces distractions and improves driving performance while performing the tasks mentioned. Further data shows that speech recognition, combined with natural language understanding technology, delivers the most dramatic benefits in reducing distractions in the car. Natural language understanding enables speech interfaces to accept multiple variables in a single voice command, such as Go to Broad Street, Philadelphia, versus responding to independent prompts for city, street and street number.

Key Findings of the 2008 In-Car Distraction Study:
-- Using the Phone - While most people think they are adept in dialing a mobile phone while driving, the study showed that even with a car kit speech input improved the ability to maintain the ideal car position by 19 percent when compared to manual dialing. Speech input was also approximately 40 percent faster in making a call, reducing the distraction period by the same amount.
-- Selecting Music - The average driver is 50 percent more distracted and takes more than twice as long for lane changes when selecting music manually versus being able to simply say the artist and song title via a speech-based interface. Swerving within a single lane was even worse without speech input, with 600 percent higher levels of distraction.
-- Setting Navigation Address - Using a manual interface to enter city, street, and street number into a navigation system results in significant safety risks. In contrast to entering information manually, voice destination entry resulted in 1,000 percent or 10 times less swerving while staying in a single lane and 30 percent less distraction while changing lanes.
-- In-Lane Deviation - The study also measured how much drivers moved from the perfect lane position. The drivers showed significantly less deviation when controlling the tested devices by voice versus manual input - with speech input resulting in 60 percent less deviation from the ideal when selecting music and 50 percent less when entering a destination.
-- Reaction Time - When required to change lanes, the reaction times when drivers were using voice commands was consistently better than when controlling devices manually. For example, making a music selection using speech was 66 percent better versus manual input.
-- Swerving in Current Lane - The study also measured how much drivers had to correct their position when staying in the current lane. When compared to speech input, drivers using manual input swerved within the lane 800 percent more for music selection, up to 1,200 percent more for navigation entry, and 300 percent more when dialing a phone.
-- Eyes on the Road - The analysis of drivers' eye movements revealed that voice commands help drivers keep their eyes on the road, reducing driver distraction to almost zero for music selection and less than 10 percent for phone dialing and destination entry. On average, speech helps keep drivers eyes on the road 200 percent to 300 percent better than manual input.

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