Hi Josh! The ONCE Foundation worked together with UNWTO to develop these guidelines, but I was not directly involved, as the leading department was the one that does work related to tourism and architectural barriers. Nevertheless, there’s lots of communication between departments and, at the beginning of the project, our department was also asked to send proposals to include in the guidelines. We sent some ideas, so, in a sense, we were a little bit involved. Glad you found it! Actually, I was not aware that it had been already released. 

Hope you’re doing good!