Yo, CM Phipps: Why doesn't this sign prevent destructive monster truck immigration?

See that sign by the stop light?

Here's a closeup. It hangs from the spot where westbound one-way traffic commences on Spring Street.

So, if no heavy trucks are supposed to be traveling past this point, how do we explain this?

And this.

And these.

Padgett and friends have filed a suit alleging that these heavy trucks are being prevented from using their rightful street (Main Street) owing to beautification changes there. Accepting these claims at face value, how does it make these heavy trucks on Spring Street any more legal?

Shouldn't they be ticketed for improperly using the street?