Plea not guilty. Call the city or stop by the construction site when they’re working and see if anyone working would be willing to give you something that states they were not on site during that time of the day. Schedule, written notice from the supervisor, something. Get her driver’s abstract from the DMV. Check to see if that zone was down to one lane (take a picture) and is she was driving during a rush-hour time of the day, state so. Build a case for your wife and ask if you can MAIL everything in, followed by a written plea (reason for pleading not guilty) to the DA. If not, bring what you have.
Evidence and doubt means more work for them if you fight the ticket. This means cutting time and corners and giving you something much smaller than if you stood there with your hands folded and said “I didn’t do it”. Build a case, hold everyone else up that just wants to get in and out, argue your points but do it professionally. Make note of even the irrelevance; “cones were not in place, no workers were there, sign has been there for days with no sign of constuction, it was one lane during heavy traffic, etc etc”. The great thing is you are right untill they prove otherwise, which is more time and money for them.
I’ve had my run ins without a lawyer, and I bet I have some of the lowest insurance rates here 