Because of the risk of malaria in Thailand we are now considering going to Morocco. I have read some interesting journeys by car in this country. When I searched on Google image for "traffic signs morocco". There appear to be quite some Arabic traffic signs. This make me wonder if it is a safe to rent a car in Morocco while I don't understand Arabic.
There is no problem driving in Morocco if you cannot understand Arabic. I think the impression you get from your Google query is not quite correct. The road signs are bilingual Arabic/French, sometimes even with pictograms:
In cities the signage can sometimes be a bit meager. Combined with the Moroccan style of drive, this makes crossing a city a bit more stressful. For overland travel, the signage is fine. Nevertheless it is a good idea to have a road map.