The Google LatLong Blog announced that you can now create your own custom driving directions in Google Map Maker. This comes in handy when Google Maps is missing roads, is mistaken on directions or if you want to make up a better route to get to your destination.
Typically, I would take you through a screen by screen on how to actually do this. But Google has already done so on this page. So if you are interested in how this works, definitely read about it over here.
Google did say this tool is not perfect but it does make for a new way of creating driving directions.