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Author ORCID Identifier


Open Access Dissertation

Document Type


Degree Name

Doctor of Philosophy (PhD)

Degree Program

Industrial Engineering & Operations Research

Year Degree Awarded


Month Degree Awarded


First Advisor

Shannon C. Roberts

Subject Categories

Ergonomics | Industrial Engineering | Operational Research


Given the prevalence of in-vehicle technologies and the critical role of visual attention plays in driving safety, this dissertation work aimed to fill the research gap that 1) little was known about the visual demands associated with a driver engaging with in-vehicle voice interfaces; 2) the concurrent effect of interacting with in-vehicle voice interfaces and other commonly discussed individual-level factors has barely been targeted. This research work was a secondary data analysis based on a large-scale field experiment wherein 144 participants had been recruited and driven a test vehicle while performing a series of tasks using voice-based interfaces. Pre- and post-drive questionnaires were employed to collect drivers’ individual-level-related data. Participants’ visual attention while interacting with voice-based interfaces was characterized by off-road glance behavior and recorded by in-vehicle cameras. Structural equation modeling (SEM) was leveraged to build a theoretical model connecting participants’ individual-level factors to their off-road glance behavior while interacting with in-vehicle voice interfaces.

Results from SEM analysis 1) confirmed that driving is complex as participants’ off-road glance behavior was significantly affected by multiple factors; 2) found that participants with higher trust in technologies actually tended to have longer off-road glance behavior as compared to those who trusted technologies less, and this might contradict previous findings and the theoretical basis of trust in a technology; 3) participants’ age and gender did have an effect on their off-road glance behavior and the findings were generally in line with relevant research; 4) participants’ previous usage of voice interfaces did not predict their off-road glance behavior while their preconceptions about technologies did. Although voice-based interfaces are designed to help reduce drivers’ visual attention required for interactions, drivers may still direct their eyes off the road and exhibit risky visual behavior while interacting with them. Besides, individual-level factors can also exert influence on drivers’ visual behavior in a way that drivers of certain groups might have riskier behavior when interacting with voice-based interfaces. To promote the general public’s adoption of in-vehicle voice interfaces and make the interaction safer, accounting for the psychological and physical factors that are properties of the human component is critical.


Creative Commons License

Creative Commons Attribution 4.0 License
This work is licensed under a Creative Commons Attribution 4.0 License.