drive-by porn
n. Sexually explicit images viewable on a video screen in a nearby vehicle. Also: drive-by pornography, drive-by smut.

Example Citations:
"It was like when a friend tells you too many details about their personal life," says Jess Mortimer, who spent an eternity stuck in a Beltway traffic jam behind some guy watching really acrobatic stuff on his SUV's television. (This type of secondhand viewing is prevalent enough to have earned its own terminology: Drive-By Porn. Several states have passed or proposed legislation dedicated to preventing it.)
—Monica Hesse, "Publicly, a whole new lewdness," The Washington Post, November 12, 2009

But always-on access will occasionally expose us — in some cases fleetingly, and in others in a more intrusive manner — to the communicating and viewing habits of others. A few years ago I recall reading news reports about "drive-by porn" — the visible display of pornographic images on video monitors inside vehicles.
—Timothy Zick, "Porn Air," Concurring Opinions, September 2, 2008

Earliest Citation:
Andrea Carlton hadn't planned on telling her daughter about the birds and bees until she was 8 or 9. But that changed the night 4-year-old Catherine spotted a porno movie flickering on a screen in a minivan nearby.
—David Runk, "Drive-By Porn," The Canadian Press, March 10, 2004

A slightly older variation on this theme is porn that you see while driving by a shop that has a salacious window display:

You won't be able to miss Object. In fact, it fairly well jumps out at you from its street-side glass display. No wonder. It was voted best "drive-by porn" in last year's City Paper, you can go inside to find all the fetish wear you could possibly want (and probably a lot you don't want).
—Liz Steinberg, "Mount Vernon features hip shops, posh restaurants and wicked bars," The Johns Hopkins News-Letter, September 6, 2001

Related Words: