This is a bad sign
Way back in 2012, I noticed a "keep left" sign that had been used in error on a road here in Silicon Valley. If followed, it would have sent cars up a one-way four-lane expressway at 45 MPH. It would have been messy. The resulting picture wound up being used as cover art for my second book.
At the time, I was wondering exactly how often they even have a use case for a "keep left" sign, given that we drive on the right. It can't be very often.
Well, yesterday, I got my answer: a case when "keep left" would actually be correct... and would be far better than what they DID install:
Yep, that's underneath highway 87 just outside the San Jose airport. It shows a "keep right" sign in a situation where you definitely do not want to do that. The intersection in question has a design which is somewhat unusual, but it's nothing new or special in 2019.
You're supposed to go to the LEFT of the island in order to complete your turns. See the cars on the other side? They are supposed to do that, too. That way we don't cross paths, and the intersection runs quickly. Normal intersections have lefts that cross, and so they have to be separate phases, and that's slow, and so on and so forth.
Keeping left is the whole point of this design, and someone obviously does not get it.
This seems to be a recent change, since if you go back in Street View, you either see no signs (for the island seems to get hit often), or, occasionally, something actually helpful:
I guess I have some calls to make and e-mails to send before someone gets creamed due to this.