Waterproof post-it notes don't exist. But if they did? Here's what I'd do. No barriers, right?
Imagine crowd sourcing taken to somewhere near the limits. Town planning. How many town planners actually live in the town they plan, I wonder. How many drive around the roads they one way systemise, how many use the ramps and diversions. Imagine if you could crowd source all the people who regularly use the physical infrastructure of the town or city where you live. All the footfall which passes across the pavements, all the people who pass through your local shopping centres shop doors. All the people who look for litter bins and can't find one, all the people who walk the streets and look for benches and can't find them. The people who cross roads and have to wait 10 minutes for a break in traffic, the people who walk along the darkened path and wonder why there are no streetlights.
Ask them. Open up your streets and ask them. Invite the curious, the residents, the armchair intelligent, the planning geeks and the planning bods from other Boroughs. Ask them to tell you where they'd like the bins to be. Where the pedestrian crossing should be moved to, why that sign is always pointing the wrong way and where the drop in the kerb is in absolutely the wrong place for the electric wheelchairs running over it. If waterproof post-it notes existed, by the end of the day, you should have a multi-coloured environment of suggestions and commentary, positive and negative, telling you exactly how the users of the world you've created feel about it when they try and interact with it.
Because waterproof post-it notes don't exist for the moment - why not use Google maps? It's got a zoom level accurate enough to suggest where a bin or a bench should be moved to. It's got a comment facility.
Ask. I think you might be surprised how many people would answer.