Comparison of the Effects of Two Push-to-Talk Button Implementations on Driver Hand Position and Visual Attention

Buttons built into the steering wheel are used in many vehicles as push-to-talk (PTT) buttons for in-car speech user interfaces. We explore the influence of such a fixed PTT button on driver hand position on the steering wheel and on visual attention while driving. We also explore these variables for a wireless PTT glove, which allows drivers to use the entire surface of the steering wheel to operate the PTT button. Participants in our driving simulator-based study were willing to take advantage of the flexibility in hand position afforded by the glove PTT button. We also found that participants cast glances toward the steering wheel significantly less often when using the PTT glove than they did when operating the fixed PTT button