To combat the reported dangers of texting while driving, many new mobile phone voice control applications and products have hit the market.
But a new study has found that voice-to-text might not be any safer than type-to-text while driving.
The study, conducted by the Texas A&M Transportation Institute, found that reaction times while texting were nearly twice as slow as when drivers were not texting, regardless of whether they were texting with their voice or their fingers.
"From our experiment, the response times and amount of time looking at the roadway was about the same when texting manually or using a voice-to-text application," Christine Yager, an associate transportation researcher at the Texas A&M Transportation Institute, told ABC News.
"I previously co-led a study that looked at the differences between reading versus writing text-based messages while driving," Yager said. I became curious how newer methods of sending/receiving text messages would affect driver behavior and safety," she said.
In the study, the researchers asked 43 participants to drive 30 mph inside marked lanes on a closed course four times. The drivers were asked not to text in the first round, to send several texts via type-to-text in the second round and then several more texts via voice-to-text using Apple's Siri on an iPhone and Vlingo's voice app on a Samsung Android in the third and fourth rounds.
During the test drives, cameras tracked drivers' eye gaze, and GPS was used to record change in lane positioning. Driver-response time was measured by how many seconds it took the drivers to press a response button after a green LED light periodically flashed on the dashboard.
Drivers reported that the voice-to-text methods felt "safer," but the difference in driver reaction times when compared with type-to-text was slim to none. Texting with Apple's Siri, on average, actually produced slower response times than the type-to-text method. Response times while using Vlingo to text were the fastest, but only by a very small margin.
When texting with Vlingo, drivers spent more time with their eyes on their devices and less time with their eyes on the road, according to the study. While using Siri, drivers kept their eyes on the road more often.
The study also found that, on average, when using the voice-to-text software, the drivers took longer to complete a text than when typing manually.
Yager said that even though each participant was given time to practice using of each method of texting before the experiment, voice-to-text software was still new to most drivers. "It would require additional research to determine whether any driving performance improvements would be observed from being more familiar with the voice-to-text software," Yager said.
"A way to relate this study's results to the everyday driver is that if a texting driver is watching the road less often and their reaction times are slower, then that driver is less able to take action in response to a sudden roadway hazard, like a pedestrian in the street or a swerving vehicle," Yager said.
Thirty nine states have already outlawed type-to-text texting, but hands free, voice-to-text remains legal in every state.