dear visitors to san francisco,
i know, i know. your arm is tired. not from bench pressing a small nation or carrying a small child like a football, but from trying to hail a taxi here in our lovely, foggy city. i've seen you waving your arms ferociously as cabs (and pizza delivery men) pass you by, and you stomp and curse and yell, but you're missing something. the big "it," so to speak. see that box atop the roof of the cab? the one that says "taxi"? is it lit all bright and yellow like the star atop a christmas tree? no? aha! san francisco taxis signal their availability by the lighted sign on top of the cab: when the sign is illuminated, the taxi is available. when it's not, that means the cabbie most likely has a fare, is going to pick up a fare, or is off duty. there's a slight chance that the driver may have forgotten to turn off the light, but don't get all down in the dumps if you get passed by. just don't waste your energy; you'll need it when touring the academy of sciences or facing down our mighty sales tax. artfully wave your arm and yell "taxi" only at cabs with the yellow light illuminated. or tip a hotel bellhop and have him whistle you a cab.