Objective: An experiment studied the frequency and correlates of driver mind wandering. Background: Driver mind wandering is associated with risk for crash involvement. The present experiment examined the performance and attentional changes by which this effect might occur. Method: Participants performed a car-following task in a high-fidelity driving simulator and were asked to report any time they caught themselves mind wandering. Vehicle control and eye movement data were recorded. Results: As compared with their attentive performance, participants showed few deficits in vehicle control while mind wandering but tended to focus visual attention narrowly on the road ahead. Conclusion: Data suggest that mind wandering can engender a failure to monitor the environment while driving. Application: Results identify behavioral correlates and potential risks of mind wandering that might enable efforts to detect and mitigate driver inattention.