From what I have seen over the last few days, the roads of the coastal strip of which Nice is a part are like unfamiliar city centres at rush hour with, of course, everything happening from the unfamiliar side. I would definitely encourage you to find the safest short route, or shortest safe route, to wherever the roads are quieter. Beyond that I cannot help, because I will be hunkering down in the shade until it is time to close my eyes and be driven back to the bloody airport.
Oh. Insect repellent.