Consider, two of the sites (one not completed?) are bordered by an enclosing, nearly perfect rectangle. Engineering types love regularity and boundaries. (I know, I are one!)
At the resolution available on google maps, the marks appear to be cleared land, similar to that around the runways of the nearby airstrip. If you were testing a vehicle, you'd want (initially) a fairly well defined path, something that wouldn't confuse it's optical sensors/processing algorithms. You'd only want to deal with terrain. (at first)
Speaking of terrain... Note that many of the (apparently) cleared swaths follow (approximately) terrain features, while other seem to cross significant terrain.
So, maybe a training/test ground where they are trying to "teach" an autonomous navigation system to cross rough terrain while holding to a basic course line?
Of course the next question is, why? Why would the most populous Country be developing un-manned systems? It would seem they could get as many drivers as they wanted. Well, maybe supply isn't the problem, maybe the environment they are headed into is. Say, north, in the winter? If you were going to head north into Siberia after natural resources, if you were going to ensure your supply lines with minimal need to support the vehicle operators themselves... The only question is, will this be a commercial undertaking, or a military one?
Speaking of terrain, many of the sites are cut through with river channels. I have no idea how often it rains there but from the looks of the place not very often. So it seems like these things are pretty old.
And on one of the sites there is a very plain fault where part of the land subsided (or rose up). Sure looks like that happened after the lines were built. Earthquake? Natural or man made?
“nearly perfect rectangle”
That cought my eye too. If they were CREATED from space the azimuth angle might be the cause.