Earlier quoted context omitted.
Then there’s an aggressive driver who sees that and realizes it hammers home the point that the yellow speed signs (vs the white ones) are not enforceable. And an enforceable sign could never be a weird number because speedos don’t have ticks but every 5mph.
The first time I drove in the US I came up to a turn with the yellow speed sign. I was going faster and I could feel my car strain to not go off the road. This is to this day the second scariest thing I've experienced in a car. After that I 100% followed the yellow signs.
I have to know! What was the scariest thing?