I'm trying to earn my Completist badges, but can't figure out how to tell where I have and haven't been. I thought I saw a gameplay tip flash across the screen at one point about unvisited streets, but I can't find a way to see it again. I even checked whether the API could be coaxed into telling me how many times I've visited a street, but no such luck.
There's also a complication: I'm colorblind. If there's a visual difference between visited and unvisited streets, I can't see it.
So how can I figure out where I've been?