What grounds if any would be likely used to strike down Minneapolis' red cars on Lake Street ban?

[MarkD]

If Robert Bork were still around, he would say that an ordinance that has long been unenforced, but then suddenly started being enforced for some reason, the first few people who get prosecuted should be allowed to go unpunished because of desuetude.

All of the current Supreme Court Justices would invoke substantive due process as a reason to strike it down if they simply don't like the ordinance.