Use your cellphone when you’ve gotta go.
MizPee says it finds the closest and cleanest bathroom by location from a cellphone. Apparently you just use your mobile browser to go to mizpee.com, click on Find toilet, then enter a location. Right now it’s just Portland, Minneapolis, San Francisco, Washington DC, Atlanta, Oakland, and San Jose but more are reportedly being added. MizPee will give provide nearby toilets, distance to that toilet, and whether or not a purchase is required.
If you need to go in another location, or even out of the US, you might want to check out The Bathroom Diaries
Whichever you use, wherever you go, just don’t drop the phone in….