Study Finds Lingering Driver Distraction from Voice-Activated Controls

Drivers using voice commands on their phones and to control in-vehicle infotainment systems incur moderate to potentially high cognitive distractions with residual effects lasting as long as 27 seconds after completing the interaction, according to a new study by the AAA Foundation for Traffic Safety.

The analysis evaluated drivers in 10 different 2015-model vehicles and with three types of smartphones while traveling at speeds as high as 25 mph.

The different hands-free systems were rated on a five-point scale related to cognitive workload based on a driver's behavior, reaction time, completion of tasks and response to road signs. Category 1 distractions are equivalent to listening to the radio; level 5 distractions are likened to taking a challenging test while driving, according to the report. AAA considers a category 2 distraction (talking on a phone) or higher to be potentially dangerous.

The average distraction level when using voice commands in tested vehicles was 3.4. Smartphones averaged 3.7. Older drivers (aged 54-70) scored significantly worse than young (aged 21-34) and middle-aged (35-53) drivers in the study. The authors note that performance for all groups improved slightly after drivers had a week of practice in a specific vehicle.

Of the 10 vehicles tested, the hands-free systems in the Chevrolet Equinox and Buick LaCrosse fared the best with each getting a 2.4 rating. The Toyota 4Runner was next-best with a score of 2.9.

The Ford Taurus, Chevrolet Malibu, Volkswagen Passat, Nissan Altima, Chrysler 200c and Hyundai Sonata were rated in descending order from 3.1 to 3.8. The Maza6 sedan fared the worst in the study with a distraction level score of 4.6, which AAA says is equivalent to updating social media posts.

Google Now was the highest rated hands-free smartphone system with a rating of 3.0. It was followed by Apple Siri (3.4) and Microsoft Contana (3.8).

The researchers note that the complexity and intuitiveness of the different voice-activated operations affects the level of cognitive distraction. After completing a command, it took between 15 and 27 seconds for drivers to reacclimate and return to baseline driving levels, AAA says. It notes that vehicles travel about 300 yards (the length of three football fields) in 27 seconds at 25 mph.

Participants were tested after being given a brief orientation on how to use a system’s voice-activated controls and retested after having driven a test vehicle for a week. A camera on the rearview mirror and a headband-mounted task-response monitor were used to assess driving performance and attention to the road. A video of the tests is available on AAA’s Web site.

AAA recommends that drivers use caution when using voice-command systems or avoid using them altogether, even when stopped at a traffic light.