Where are the bumper stickers?

Most of us, we're told, have already picked our political team for this election. Some of us even like our guy, enough. But the candidates don't ignite the kind of ardor that prompts supporters to broadcast their love all over the roadways.

Bowen, who lives near San Francisco, says he has seen fewer bumper stickers there as well.

"It surprises me," he says, and he thinks it may correlate to the apathy he senses among Californians, who feel their votes aren't likely to determine who wins.

3. The Trash Factor

Bowen says fewer cars, especially expensive ones, have an old-fashioned bumper, the big rubber kind that just begs for a bumper sticker.

What's more, he notes, for some people, the bumper sticker conveys "an image of trashiness."

4. Fear

Bowen says bumper stickers have grown more aggressive. "I Love My Candidate" has given way to "I Hate Your Candidate."

In a polarized world, it can be dangerous — or feel that way — to flaunt your "Obama bin Lyin'" sticker or the one that says "Honk if You're Voting for Romney So I Can Give You the Finger."

At least on Facebook, you can speak your mind and not worry about your car getting keyed.