Custom map made, strange placement of white marker dots

[Snowpelt]

The route markers are all determined by googles imaging data unfortunately. The very short version is that we have two images, the one you are in(a) and the one you are going to (b). Google tells us how those images are connected in streetview, and we draw the path to using those directions from image a to image b. Switching sides of the road and staying there is usually the result of Google using images from a different car on a different day. Corners and veering are just issues with the depth data the car provided.

So unfortunately there is not much room to improve these types of issues.