Hello:
Well....... in Chicago we have a Lake Shore Drive that goes North/South. But..... for 1 (one) block it turns East/West before going back North/South again.
The sign is necessary because the taxpayers have far too much money and would likely be confused by a road that doesn't go straight.
Also the Mayors brother-in-law has a sign making business...
Seriously, I think the sign is in Chicago where, in addition to a T intersection, there is an angle street that joins the other two.
Also, the Mayors brother-in-law has a traffic light control business.
Do not confuse him with his other brother-in-law who is a personal injury attorney, his office is on the corner where those lights are located by the way.
Kind Regards,
Ron