With texting so clearly dangerous while driving, users and vendors have turned to speech-to-text technologies as a safe alternative, perhaps to no avail.
According to a study published by US road safety group the AAA Foundation, speech-to-text technologies are more distracting than talking to other passengers in the car. The research backs up a simpler study carried out earlier this year in Texas.
To test cognitive distraction, the AAA conducted three experiments. In the first, volunteers performed eight tasks, and in the second, they carried out the same tasks while driving in a simulator. Finally, they drove an instrumented vehicle through a city residential area. The experimental tasks included listening to a radio; listening to an audio book; speaking with a passenger; using a hand-held mobile phone; using a speech-to-text interface; and a combination of memory and true/false maths problems.
In the laboratory baseline, the research found that compared to a single-task reaction time of about 460 milliseconds, speech-to-text operation had an impact similar to using a hand-held mobile, slowing participants' reaction times to around 570 ms.
In the driving simulator, speech-to-text operation was worse (noting the large error bars) than using a hand-held mobile phone – drivers' mean braking reaction time while using the mobile was around 950 ms, while a driver using a speech-to-text interface had a mean reaction time of about 1050 ms.
Other symptoms of distraction the researchers measured included “suppressed brain activity … missed visual cues, and reduced visual scanning of the driving environment (think tunnel vision).”
As the AAA Foundation notes: “Though shipments of these systems are expected to skyrocket in the coming years, use of speech-to-text communications presented the highest level of cognitive distraction of all the tasks we analysed.”
On the other hand – and apparently refuting an urban myth that car radios are just as great a distraction – the research found that listening to the radio or audiobooks only caused “minor increases in cognitive workload”.
The research was conducted with the University of Utah. ®