This feels like a discussion in which "NO THROUGH TRAFFIC" signs are a proposal, something abstract, that doesn't exist. "NO THROUGH TRAFFIC" signs are everywhere, and they are routinely ticketed. If your friend lives on the street you're ticketed on, you probably won't get a ticket. If they don't, you probably will.
This is a nonsensical article. No Through Traffic signs aren't unconstitutional; they're enforced all over the place.
It's possible that this particular township didn't have laws on the books making the signs enforceable, and the police and residents put signs there anyways. But unless Alabama has a truly wacky state constitution, that problem is a city council meeting away from being fixed.