Putting private signage in the road is illegal anyway.
We have a retired ex cop in the neighborhood that decided all on his own that 15 was the new speed limit on the street instead of the posted 25 by the city.
He used to call the police on me for running his signs over until the officers told him he was violating a city ordinance and if he did it again they were going to fine him.
He doesn't like me very much for some reason. :D