Shenzhen has quite severe elevation differences (which is why a lot of it is unbuilt, even though land values are extremely high) but the bus network was planne

Shenzhen has quite severe elevation differences (which is why a lot of it is unbuilt, even though land values are extremely high) but the bus network was planned to run mostly on the flat bits. HK, being heavily built up already, does not have the luxury of being able to do such planning.