Outbound Texting

Abstract

A speech-based system was evaluated to assess general task and on-road performance across vehicular control and subjective measures. The system under evaluation enabled users to send text messages and obtain route guidance through destination entry while driving. A brief introduction to the speech-based system and its capabilities was provided to participants before they were asked to complete three practice tasks. General observations of these initial uninformed interactions (i.e., absent assistance by the experimenter) with the system indicated that the system was intuitive and easy to use. Errors, when observed, were commonly related to word recognition. Participants were then instructed to navigate a closed test track at 72 km/h (45 mph) while engaging in nine secondary tasks: three manual modality texting tasks, three equivalent voice modality texting tasks, and three voice modality destination-entry tasks. As expected, driving performance measures, glance behavior, and subjective ratings were all significantly degraded during manual texting tasks as compared with similar tasks completed using voice commands. Performance during speech-based destination tasks was similar to that observed during speech-based texting. Subjectively, participants generally believed that tasks requiring the use of the speech-based interface could be accomplished safely. The majority of participants (83%) expressed a desire to have this speech-based interface available on their next vehicle.