Cars have changed from pure transportation devices to fully interactive, voice-based systems. While voice interaction in the car has previously required on-board processing, the growing speed and ubiquity of wireless technologies now enable interaction with a distant source. Will the perceived source of the information influence driver safety, responses to the information, and attitudes toward the computer system and car? A between-participants experimental design ðN 1⁄4 40Þ of computer proximity—in-car vs. wireless—using an advanced car simulator, found that people’s driving behavior, verbal responsiveness, and attitudes are affected by computer proximity. A path analysis shows two counterbalancing effects of computer proximity on driving behavior: drivers feel more engaged with the in-car system than the wireless system, which leads to safer driving behavior; however, drivers also drive faster while using the in-car system than the wireless system, which leads to more dangerous driving behavior. Consistent with greater feelings of engagement with the in-car system, people also feel less discontentment with the in-car system and self-disclose more to the in-car system. Positive perceptions of information content also lead drivers to be more persuaded by driving recommendations. Implications for the design of wireless systems are explored. r 2006 Elsevier Ltd. All rights reserved.