Legal liability for noncompliant traffic control devices.

So there’s a document called the MUTCD, or manual of uniform traffic control devices, both federal and local versions, that state where paint striping, traffic signals, signs, and such may or may not be used.

If a new installation is put up in violation of these standards, is that a potential defense to a traffic citation, or is the agency exposing themselves to liability if an accident occurs? Say a driver gets a ticket for running a red light that is only 8 inches instead of a required 12, or a driver fails to yield and causes an accident. when turning left under a green light where standards require a flashing yellow arrow?

Yes proving the traffic control devices are not in compliance could be used as a defense. I will leave the civil part up to someone else.