This US simulator study compared the effects of two different voice interfaces and the standard iPod touch interface on safe driver performance, in terms of glance durations, task completion time, hazard anticipation and other measures. A total of 17 participants were involved in the study, ranging in age from 18 years to 30 years. Each driver was required to navigate eight different four-minute drives using the simulator. While driving, participants were asked to retrieve a song from the music library using the two voice interfaces and the iPod touch interface. Results indicated that the voice interfaces reduced the total time drivers spent with their eyes off the road. The voice interfaces also reduced the number of long glances away from the forward roadway, and the total number of glances away from the roadway irrespective of duration.
The results indicated that vice interfaces can offer a real advantage over touch interfaces on some measures of safety. Well-designed voice interfaces can reduce the total time drivers spend with their eyes off the road. As such, researchers proposed that lawmakers should critically examine which devices and styles of interface will be permitted for use in vehicles. Evidence suggests that any interface that requires a combination of touch and visual processing driving routine driving may be unsafe and this should be a consideration during the development of legislation.
Garay-Vega, L., Pradhan, A. K., Weinberg, G., Schmidt-Nielsen, B., Harsham, B., Shen, Y., … & Fisher, D. L. (2010). Evaluation of different speech and touch interfaces to in-vehicle music retrieval systems. Accident Analysis & Prevention, 42(3), 913-920.