I drove from Pretoria to the Sun City / Pilanesburg park area and did not find the signs and markings to be at all clear on the major motorways around Pretoria (though they seemed clearer once I got onto the smaller roads). The rental car company map was so vague and the signs so confusing that we got turned around multiple times and a drive that should have taken about 2 hours ended up taking over 4. I think that in general the signs on the US highway system are far clearer than those I saw in that area of South Africa.