Yes it is true, Sharia law which is the only law in Saudi, does not concern itself with driving rules.
We were warned about how dangerous driving could be.
I worked for Aramco the Saudi oil company, if we got into a road accident there were company negotiators who would come out and sort the problems out for us. Always assuming we were still alive of course.
We were also told never to use a Saudi taxi, as if there was an accident according to the will of Allah it was our fault. The logic being that if we had not taken the taxi it would not be in the place where the accident was at the time it was due to happen, therefore it was the passenger's fault not the taxi driver. There were company Taxis which were insured but ordinary ones were not, so a passenger would have had to pay the entire costs if the taxi crashed.