Silk Road evolved as 'grass-routes' movement
phys.org
phys.org
Historically, the Silk Road (in this region) ran from Kashgar in the Tarim Basin to Osh in the Fergana Valley, although I'm not exactly sure which passes were taken. It always struck me as odd that the Silk Road didn't pass through the Kyzyl-Suu river valley, which is the only road link you can see today on Google Maps. On the other hand, this visualization does seem to reinforce the idea that natural trading paths did not cross the mountain ranges in ways that would reinforce that link but rather focused on a more circuitous route via the bulk of Kyrgyzstan.
Basically, a human telegraph for tangible goods, with a mark-up at each step. With that in mind, the price of cloves in Medieval Europe starts to make a lot of sense, as do the crazy stories behind some of the spices. See: The alleged source of cinnamon!
The following map gives me some context:
https://upload.wikimedia.org/wikipedia/commons/7/74/Silk_rou...
Red are land routes and blue are the sea/water routes. The OP's map appears to be the area above China and India where you see two parallel red lines.
The lines on Wikipedia's map are so thick that they obscure most of the relevant features in the image.
The bounds of the image on Google Maps is roughly this: https://goo.gl/maps/akaV2mcgUXv (I don't know how well the exact extent matches up). Bishkek and Almaty are at the northern edge of the image, Kashgar at the southern edge, Karakol at the eastern edge, and Kokand at the western edge. In simpler terms, just make sure you can see all of Kyrgyzstan and not really much more than all Kyrgyzstan.
I was thinking of a different Silk Road that was less grass-routes movement and more movement of grass and 'roots'.