Please ignore this sign for everyone's sake
I want you to visualize driving somewhere. You're in the Valley, and you're driving down Central Expressway. It's 50 mph, 3 lanes on either side, and it's generally pretty zippy. You pass over Bowers and prepare to jump onto San Tomas in order to reach El Camino Real.
To do this, you have to exit to the right, loop around a little bit, and then turn right some more and merge into traffic. You exit, and notice that you are in fact on a small road with a double yellow stripe down the center. There is traffic coming the other way, presumably from San Tomas (where you soon will be) going to Central (where you just left).
You reach the very bottom of the ramp where the lanes split back up. That's when you see this:
Yes, according to that sign, you're supposed to keep left at that divider. If you were to foolishly follow those instructions, crossing the double-yellow to do so, you would wind up facing into oncoming traffic. Worse still, there would be no way out of it for several hundred feet since the next set of exits/entrances is back a ways -- Owen Street, for those keeping track.
I guess either County Roads is on some seriously good crack, or some evil "prankster" is trying to kill people. I'm going to report it to the appropriate people (including Mr. Roadshow at the Mercury News), but I knew I had to share it here, too.
Hopefully it won't stay up too much longer.
December 17, 2012: This post has an update.