In 1982, despite working for a sailing company, I spent quite a lot of time on the road traveling between the marinas of Bodrum and Kuşadası. I enjoyed these bus rides as I had a chance to see inland Turkey and get a glimpse of the places I would spend the next 18 years visiting, although I didn't know that then. I spoke only a few words of Turkish relating to drink and food, (in that order), couldn't ask any questions, so drew my own conclusions from what I saw. Frequently on the roads I noticed circles of stones, placed, with care it seemed, to make the passing cars swerve to miss them. The bus driver would mutter under his breath as he had to swing the bus into the path of oncoming vehicles to avoid the stones. I was a recent archaeology graduate who had been working in Greece and Italy and this may have influenced my interpretation of these rocks. I decided that they were probably sacred sites (number one archaeological answer for everything) or the scene of a fatal accident and the drivers were saying a prayer as they passed by. Just as the Greek and Italian drivers did as they passed way-side shrines. I believed this for a whole season. I only learnt the prosaic reason for these stone circles when the mini bus I was traveling in to Milas stuttered to a stop. We all trouped out and stood by the side of the road and I watched the driver collect big rocks and place them round the van. A small boy was sent off and half an hour later he returned with an open cheese-tin of diesel and we were able to carry on our journey. Leaving a circle of stones behind us.
I haven't seen any stone circles in the road since I've been back in Turkey. I suppose all the new Renaults and Fiats don't break down and as there is now a petrol station every few hundred meters, no one runs out of fuel any more.