Improving Driver-Smartphone Interactions

Accident Analysis & Prevention

November 21, 2023

In a closed-track study, voice-based and manual driving modes were shown to reduce driver distraction 

An analysis of driver inattention funded by the National Highway Traffic Safety administration found that drivers who take their eyes off the road for just two or three seconds can significantly increase the risk of a crash, meaning that reducing smartphone distractions for drivers could boost public safety. Using voice-based or manual driving modes on smartphones can reduce the visual demands on drivers, according to a recent eye-tracking study of participants on a closed track. 

The completed study, "Visual and Cognitive Demands of Manual and Voice-Based Driving Mode Implementations on Smartphones," was published by Exponent human factors scientists Chris Monk and Benjamin Lester, in collaboration with user experience researchers in private industry, in the July 2023 issue of Accident Analysis & Prevention.

Bigger buttons, larger icons, and voice-based interactions are three primary features offered in driver mode to avoid placing extra visual and cognitive demands on the driver. Using eye-gaze recordings on a closed test track, the authors compared two driving mode implementations, voice and visual, as well as the conventional smartphone interface, as motorists completed five typical tasks.

The study results delivered positive evidence that voice-based driving mode implementations reduced visual demand from mobile devices while driving, as well as subjective ratings of distraction. While voice-based driving mode generated the most positive results, the authors also suggest that manual driving mode implementations have the potential to reduce visual demand and subjective levels of distraction, relative to drivers using the standard mobile operating system.

The authors note that while mobile phones are not the sole source of in-vehicle distraction, their high prevalence in everyday activities, including driving, make them a special safety concern.

Person holds a phone in right hand while driving
Accident Analysis & Prevention

"Visual and Cognitive Demands of Manual and Voice-Based Driving Mode Implementations on Smartphones"

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From the publication: "Rather than trying to influence drivers to minimize interactions with their smartphones, which has largely been unsuccessful, a different approach focuses on entirely removing drivers' abilities to engage with their mobile devices while driving."