For someone with limited mobility, using the sidewalk in a new area can be like driving with no directions, hitting dead end after dead end: there are many obstacles that can prevent access (no curb ramps, too steep of hills, bad surface conditions) and there are next to no resources available that provide this information.
The goal of AccessMap is to enable safe, accessible trip planning on pedestrian ways for people with limited mobility. To meet that end, the people working on the AccessMap project develop tools for trip planning as well as tools for gathering and maintaining open data about sidewalks, curb ramps, construction information, etc. We are starting with Seattle, but hope to expand to other locations soon using the OpenStreetMap-based efforts of the OpenSidewalks project.