This route is 140 km, 2h45 driving time, from Aix-en-Provence to Arles, via Martigues, Istres and Salin-de-Giraud.
A side trip from Istres to Miramas and Saint Chamas adds 30 km (40 min), round trip.
Route. [53 km, 40 min] Go south out of Aix and get on the A8/E80 autoroute westbound, and follow the signs for the A8 direction Marseille. In 3 km take the A51 direction Martigues (going south towards Marseillel). Another 16 km merge onto the A7. In 3 km exit to the A55 and continue for 23 km to exit 13a/13b for Martigues.
The area between Marseille and Martigues is pretty built-up, but there are interesting villages along the south coast, and some nice places in the hills along the middle of the area.
Route. [15 km, 23 min] Go north on Ave du President Allende along the shore of the Etang de Berre, that merges with the D5 to Istres. There are various sites along the way, including fortified ruins at Saint Mitre-les-Remparts.
Route. [34 km, 60 min]
Southwest from Istres on the N569, past Fos-sur-Mer towards Port-Saint-Louis-du-Rhône — it's all very industrial. Just outside Port-St-Louis, go northwest, following the signs for the "Bac de Barcaran", the little ferry boat that crosses the Rhone to Salin-de-Giraud.
• Alternate Route. [10 km, 14 min] Go north from Istres directly to Miramas.
• Alternate Route. [5 km, 5 min] From Miramas southeast to Saint Chamas.
• Alternate Route. [44 km, 1h18 min] Retrace your route northwest to Miramas (5 km) and southwest on the N1569, bypassing Istres. Follow signs for Port-Saint-Louis-du-Rhône, then on to Salin-de-Giraud.
Route. [38 km, 41 min] Take the main D36 road north from Salin-de-Giraud to Arles. There are some little roads along the way for exploring the rice paddies and bird marshes of the eastern side of the Camargue.