A few advices if you use your car.
On the highway, EVERYWHERE in the departement, speed limits are under 110km/h. It is even 90km/h around Nice, North of the city. (Tunnels, slopes...) Usually it is 130km/h in France.
The roads leading to the valleys (Var, Vésubie, Tinée, Cians, Loup, Roya...) are built under cliffs, in gorges. There are important risks of falling rocks. This is especially true if it rained shortly before. In winter, the hazard is even greater, frost spliting rocks. Despite the impressive protection nets be careful and expect rocks on the road behind every curve. Do not drive too fast.
If you go to Nice, you can park your car for free using special lots if you use then the buses or streetcars. See this article to have details on driving and parking in Nice.
To find out which roads are closed or under work, use this official site.