Until further notice: Euro 3
All vehicles entering require a permit. Vehicles of ‘Drivers, couriers and suppliers’ also need to be accredited, and to be able to be accredited they need to be at least Euro 3. Other categories of vehicle entering do not have a Euro standard requirement.
key: covers all the shaded areas
Has signs similar to this, a banned vehicle sign with the requirements below:
A permit is always required. For the trip types affected by the Euro 3 requirement, permits allow entry:
05:00 – 11:30 every day for vehicles in delivering newspapers
06:00-20:00 for vehicles used for transporting medicines
5:30-14:00 and from 17:00-22:30 for vehicles transporting food
06:00-11:30 and from 16:00 -17:00 on weekdays for express courier services
06:00-11:30 weekdays for all other trips
Different types of permit allow entry at different times, please see here
There is currently no Italian national scheme, but regional as well as individual city schemes.
Zona a Traffico Limitato (ZTL) or Limitazioni della circolazione, the general name for all access regulation schemes, also used for Low Emission Zones.