Public transport is practically non-existent in Namibia. The roads (about 5.000 kilometres of tarred road and almost 40.000 kilometres of gravel or sand roads) are usually well maintained and fairly easy to drive.
On the road to Etosha
Even if the roads are usually well maintained, every now and then you will find in Namibia complete sections of very uneven, corrugated parts, which are very specific to Namibia.
The grooves - usually of a depth up to 10 centimetres - can shake up vehicles and passengers in a very unpleasant and extreme manner.
Locals recommend to just "fly" over these tracks, by driving sufficiently fast so the wheels don't dip into each single groove. The ideal speed is apparently around 80 kilometres per hour.
It however requires a certain amount of skill and lack of fear for the well being of your car, at least for the first few kilometres!!!
Globally, you do not need a 4x4 to travel in Namibia. Even for Sossusvlei, it is possible to drive there with a sedan car or a combi, as long as you have spare tyres due to the many heavy gravel road.
In our case, from Windhoek to Sossusvlei, through the mountains, our combi exploded in total 3 tyres due to the rocks and gravel!!!
It is apparently only necessary to have a 4x4 in the Kaudom National Park, for Kaokoland and for drives through real dune sand or in riverbeds (when they are not dry).
You usually cover vast distance without to see anybody, except for some remote small town where it is pleasant to stop for a rest.
From Swakopmund to Etosha, you will find also frequently enormous ant towers which are endemic in the area.