This is the “End of the Road” sign. There is no more road here; turn around! (In this particular example it is obvious you’re at a dead-end, but other times like in the dark & rain, it is much more difficult to tell and this sign can be very helpful)
This one is similar. This is the end of this particular road, but you can (or should I say you have to) turn left onto a different road at this point.
Notice how it’s similar in design to the checkered flag indicating the end of a car race. Just something I noticed one day while day dreaming.