I was once listening to Diana Gabaldon's Outlander on the car's CD player, back when it worked, before that ugly eating-the-parking-lot-ticket incident... ahem, anyway! When the audiobook used to loudly recite to me, I'd drive along, listening to the characters troubles and their (Outlander being racy in part), um, romantic interludes. Except for at the traffic light. There I was, listening, and as the narrative got warmer, the guy outside with the cardboard sign got closer, and I turned the volume lower, so warmer, closer, and lower, and so on until in pure embarrassment I hit the "Pause" button.
Ridiculous but true. It's the same flinching that keeps me from reading certain books on the train in case someone looks over my shoulder.
public domain + Wikimedia mashed
An earlier post on books on CD in the car here