Computer-based, in-vehicle information and communication systems (cell phones and navigation systems) are expected to become more common in the near future. This article reports on a driving simulator experiment that was conducted to determine the effects of three different methods of entering addresses into a navigation system during driving. The methods were: word-based speech recognition, character-based speech recognition, and typing on a touch-screen keyboard. For each method, the authors measured vehicle control and task measures, glance timing, and subjective ratings. During driving, word-based speech recognition yielded the shortest total task time (15.3 s), followed by character-based speech recognition (41.0 s) and touch-screen keyboard (86.0 s). The standard deviation of lateral position when performing keyboard entry (0.21 m) was 60% higher than that for all other address entry methods (0.13 m). The mean speed dropped by 1.8 kph when participants entered an address using any of the address entry methods. A significant reduction in vehicle control (lane departure, speed reduction) associated with address entry using a touch screen leads the authors to conclude that the use of speech recognition is favorable. The authors caution that speech recognition systems with visual feedback, even with excellent accuracy, are not without performance consequences (including some degradation of vehicle control).
Abstract