Between 15. November and 15. april it is are mandatory to use winter tires or to have chains in the car.
This rule applies locally for specific stretches of roads in Italy, especially for many roads in northern Italy and in the mountains where there may be snow in winter. This applies to almost all the roads near La Tornaia. If you get stopped without winter tires or chains in this period, you may get a fine of between 80 € and 318 € *.
As this is local policy, there are few (or none) of the car rental companies that rent cars with winter tires or chains in the car without beeing asked specifically. Therefore, one should be sure to ask about the chains when renting a car in winter. It tends to cost about 35 € extra.
* 12th of november 2012