I have pasted this out of another persons post.
Also be sure to inform yourselves about ZTLs so you don't get hit with hundreds of euros in fines a few months after you return home. You absolutely do not want to drive into Florence; Siena has a ZTL and probably others on your list. This may argue for at least some train travel.

What is a ZTL?????
Thanks
Shrink

Zona a Traffico Limitato - a zone within a town or city that only residents with proper permits can park in. If you enter one or park there, cameras will see you, notify your rental car agency, which will fine you for transferring information to the local police, and then you'll be fined by the local municipality. The fines can double or more between the time you make the infraction and the rime you receive the bill. If you don't pay it you may not be able to rent again.

Just to clarify, the most common infraction is driving through, rather than parking in, a ZTL. Familiarize yourself with the looks of the ZTL signs and plan your routes to avoid them. Last night, I wrote to the TI in Trapani, Sicily, asking for help with the route from Erice to parking lot in Trapani, that would get me there and back without entering a ZTL. They very nicely and quickly replied. I plan to get the same information for one or maybe two other drives.

There are other infractions that can get you caught on camera, such as driving in a bus lane. I avoid driving in cities in Italy (where I live) unless I know the city very well or have some particular reason why the train won't work.

There is no standard ZTL sign. The most common type has a red circle on a white ground, with a list of hours and exceptions. (Most ZTLs are not active 24/7.) However, there are many types of sign. Some cities now have something like a miniature traffic light, or an electronic sign that says, "Varco aperto" when you're allowed to pass.
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There are a couple of ZTL type signs/lights on this page, good info

The Truth about ZTL zones: Avoiding Tickets in Italy - GRAND VOYAGE ITALY

Yeah, but don't look at them, because there might be other types, and familiarizing yourself with any of these will surely come back to bite you. Sheesh.