Roundabouts are called 'traffic circles'
Traffic lights are called 'robots'
There are many more 4-way stop signs, including on major roads.
Arrows painted on roads are used to indicate lane splitting into two rather than an upcoming intersection in the road.
There are people in parking lots wearing fluorescent vests who "look after the cars". They may be employed by the owner of the parking lot, but might just be hoping for a tip. You may see people leaving them a tip of some coins e.g. 1-2 rand.
Watch for animals such as a baboons on the road.
Trucks and slow vehicles may pull off onto the shoulder to allow you to overtake. They will sometimes signal that you should overtake by putting their right blinker on.
A general rule: 'yield to traffic approaching from the right'.
City speedlimit: 60km/h
Highway/freeway speedlimit: 120km/h
Police use individual speed cameras, so your vehicle's speed is measured once and if your speed is over the limit, you'll get issued with a fine (they don't use the average speed over a certain distance as measured by two cameras placed some kilometres appart).
The highways in the Gauteng province have 'etolls', measured by gantries across the highway, some people pay their toll bills, some people don't.
Drivers often don't use their indicators when turning.
Minibus taxis often stop at any spot along the road, without pulling off.
Many larger vehicles (trucks, buses) aren't roadworthy (brake lights and indicators not working, and no emission control on the exhaust fumes).
Beware of pedestrians crossing the road at any spot they wish (jaywalking isn't enforced).
You may also find pedestrians and cyclists on the highway.
No cycle lanes in the cities, they mostly ride on the shoulder of the road.
Watch out for potholes and unmarked speed bumps.
When the traffic lights are malfunctioning or are completely off (this happens a lot), treat them as a 4-way stop, and make eye contact with other drivers to make sure they're not going to skip the intersection without stopping.
Always keep your windows closed and don't interact with beggars or vendors at traffic lights.
Keep your cellphone, wallet, purse out of sight (don't leave it on the passenger seat).
Keep your vehicle doors locked at all times.