Also graying, addled leftovers from the 1960's and obvious homosexuals.
Plenty of '0' stickers on old Volvos and Toyotas with educator and local college faculty vanity plates on the Connector each day. Don't think I've ever seen one on a full sized pickup. Strange.
I saw two yesterday in the People’s Republic of Tucson, but on our side of town (conservative side), so I was shocked. One was, as per usual here, a PT Cruiser. The other a small sedan (not a Prius for once). I saw one one time in two years on a pickup truck.
Like others noted, the drivers seem to be either early 20s or aging, greying, uncombed, angry hippies.