The EU-funded CAP4Access project aims to make the environment of people with walking disabilities, especially wheelchair users, more bearable. CAP4Access provides an OSM-based platform for collaborative marking of locations in terms of accessibility and navigation. In addition, external data sources for OSM will be developed. For example, the data set of the city of Vienna on sidewalk lowering was integrated into OSM in order to be able to take it into account when navigating.