Speech-based E-mail and driver behavior: effects of an in-vehicle message system interface

Area of Science:

• Human-Computer Interaction
• Cognitive Psychology
• Transportation Safety

Background:

• Advanced mobile office technology enables drivers to process information while driving.
• Speech-based interfaces aim to reduce driving interference but can still cause cognitive distraction.
• In-vehicle messaging systems present a potential safety concern due to cognitive load.

Purpose of the Study:

• To investigate the impact of an in-vehicle simulated email system on driving performance.
• To compare the effects of system-controlled versus driver-controlled email delivery.
• To understand the cognitive demands and distraction levels associated with mobile office technology in vehicles.

Main Methods:

• Utilized a high-fidelity, fixed-base driving simulator for a car-following task.
• Tested 19 participants under virtual traffic scenarios with varying driving demands.
• Analyzed driving performance metrics including headway, braking anticipation, time to collision, and steering inputs.

Main Results:

• Drivers adopted longer headways but exhibited reduced braking anticipation and time to collision.
• Processing emails led to decreased reactivity, evidenced by fewer steering wheel inputs.
• Driver control over email delivery generally improved performance, but cognitive costs were noted.
• In demanding traffic, driver-controlled systems showed reduced braking anticipation even without active email interaction.

Conclusions:

• In-vehicle email systems, even voice-controlled ones, can distract drivers and impair performance.
• Driver control over email access can mitigate some negative effects but introduces additional cognitive load.
• Findings suggest careful design is needed for speech-based in-vehicle messaging systems to minimize safety risks.