Wow, very cool, I work with the Blind in Vancouver, WA and they have very similar challenges with varying and unpredictable sidewalk conditions. And as a bike rider we have similar issues with poor street conditions like pot-holes, drop-offs, and dangerously narrow lanes. Seems like your app could benefit many users and scale well for any geo. With some creative marketing we could generate an army of crowd-sourced input for it - Bravo!