Speed limits, which licences are valid, restricted-traffic zones, compulsory child seats and the habits of Sardinian roads that no sign explains.
In Italy you drive on the right and overtake on the left. General limits are 50 km/h in built-up areas, 90 on secondary rural roads, 110 on main rural roads and 130 on motorways — but Sardinia has no motorways: the main arteries, such as the SS131 that crosses the island, are dual carriageways with posted limits between 90 and 110. The sign always wins over the general rule.
Drivers who have held a licence for less than three years face lower limits (100 km/h on dual carriageways, 90 on rural roads) and a zero alcohol limit. For everyone else the limit is 0.5 g/l, which an aperitif and dinner reach faster than most people expect — and checks on the coast roads in summer are real.
Licences issued in the European Union and in the United Kingdom are valid with no formalities. Licences issued outside Europe require an International Driving Permit alongside the national licence: you apply for it in your own country before travelling, and there is no way to fix it at the desk.
Three obligations that often surprise visitors: dipped headlights on even during the day outside built-up areas; a child seat or booster for children up to 150 cm tall or 12 years old; and a high-visibility vest, to be worn if you step out of a car stopped on the carriageway outside town, together with the warning triangle. All of these are in our cars.
Historic centres — Cagliari, Alghero, Bosa and many villages — have ZTLs, restricted-traffic zones with cameras: driving in means a fine that arrives months later. The practical rule is to park outside the walls and walk. Blue lines mean paid parking at a meter, white lines are free, yellow lines are reserved.
Then there are the habits no sign explains. Roads to the beaches narrow and sometimes turn to gravel in the final kilometres: go slowly, and a small car is often handier than an SUV. Inland you will meet free-roaming sheep and cattle, especially at dawn and dusk. Village petrol stations close early and stay shut on Sundays: fill up when you can, not when you need to.