The road conditions are not ideal though, poor road markings, road conditions, other drivers not following the rules of the road. Hardly a place to test cars.
However, as someone who regularly visits and drives in a 3rd world country, there's a "vibe" to it if you will, and once you learn the vibe it becomes natural. (It seems to be that people respect the laws of physics over the laws of the land, if you will) If you train the cars on a 3rd world country's driving patterns, further refinement will be necessary to fit in better in a more developed country. But early on it will deal with stuff like driving on a road with no lines at the edges or between lanes, one lane bridges, sharing the road with pedestrians, cyclists, motorcyclists, and animals, etc.
And broadly speaking, with more varied training data you can achieve better out of sample results.
In Vietnam the effective priority of vehicles is "biggest first". A neural net trained in that environment won't be very useful in the UK, where priority is defined by road markings and street signs.