Road creation from image file?

I've been researching city/town creation for a game I'm working on, and have been having little luck with road system creation.
There are a ton of amazing road creation tools for Unity, I find that they all require hand placement to my knowledge.
Are there any road tools out there that would take a black and white top-down image of a road system, and generate something from that?
Alternatively, does anyone know of a road system tool that would let me click and drag full length streets, and generation cross sections were it would overlapped with other roads?
Any brainstorming help would be much appreciated. I'm trying to find a quicker workflow for this larger task, if possible.
Thanks!