Speech-to-Text Unsafe for Drivers

Drivers heavily distracted by hands free texting function in cell phones

/ Author:  / Reviewed by: Robert Carlson, M.D

(RxWiki News) Drivers can have their hands on the wheel and eyes on the road and still be distracted. Using a speech-to-text cell phone function while driving may still be dangerously distracting.

A recent study tested the levels of driver distraction with specially fitted electronic devices to measure reaction time and brain waves.

The results of the study found that hands-free cell phone use is about as distracting as hand-held cell phone use and that speech-to-text cell phone functions were also highly distracting.

"Don’t use speech-to-text while driving."

David L. Strayer, PhD, professor of psychology at the University of Utah, led an investigation into the safety of hands-free cell phone use, either talking or texting, while driving.

Multiple previous studies have shown that drivers' lack of attention while driving is responsible for a large number of car crashes.

While drivers must keep their eyes on the road to maintain safety, mental distractions, such as talking on the phone or using voice recognition text functions, may get in the way of safe driving as well, according to the study authors. 

Drivers have a certain amount of mental resources to perform a task. If a person is doing more than one mental task, such as driving and talking, their mental resources are divided.

For this study, the researchers performed a series of tests on 38 adult volunteers to gauge mental function while driving distracted.

Drivers were fitted with a skull cap that had a camera to track eye and head movement, a reaction time sensor and an electroencephalographic (EEG) sensor to measure brain wave activity.

The drivers wore the caps while performing eight different tasks that required mental resources.

The eight tasks were performed for 10 minutes each. The reaction time sensor in the skull cap flashed a red or green light to measure the reaction time for eye and head movement during each of the eight tasks.

On a scale from 0-5, the researchers averaged the mental distraction levels of the drivers for each of task:

  1. Driving with no distractions scored 1.0
  2. Driving while listening to the radio scored 1.21
  3. Driving while listening to a book on tape scored 1.75
  4. Driving while talking to a passenger in the front seat scored 2.33
  5. Driving while talking on a hands-free cell phone scored 2.27
  6. Driving while talking on a hand-held cell phone scored 2.45
  7. Driving while talking into a speech-to-text cell phone function scored 3.06
  8. Driving while performing a math and memorization exercise scored 5.0

The researchers found little difference in distraction levels between hand-held cell phone use and hands-free cell phone use, but found that the speech-to-text cell phone function significantly distracted the drivers.

“The data suggest that a rush to voice-based interactions in the vehicle may have unintended consequences that adversely affect traffic safety,” wrote the study authors.

“Our research shows that hands-free is not risk-free. These new, speech-based technologies in the car can overload the driver’s attention and impair their ability to drive safely,” Dr. Strayer said in a press release.

The results of this study were published in June on the AAA Foundation for Traffic Safety website.

No outside funding was used for this project. AAA Foundation for Traffic Safety is a non-profit research organization. The authors declared no conflicts of interest.

Reviewed by: 
Review Date: 
June 10, 2013
Last Updated:
August 7, 2013