The effects of a Head-Up-Display and gesture-input interfaces of a personal digital assistant device on driver behaviors were examined. During car-following driving, the HUD remarkably improved the number and duration of glances at the digital device, and the gesture-input facilitated manipulations which did not require glances at the device. Regardless of the driver interfaces, however, in-vehicle tasks having large cognitive demands increased vehicle lateral displacement variability and headway distance variability.

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[in Japanese]

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