I am looking for a dataset that includes freeway exit and ramp signs used for navigational purposes. Signs such as "Exit 25, Campbell Avenue" or a sign indicating to keep right to merge onto a different freeway. Does this data exist in an open source format? If it is compatible with OSM data that would be amazing, but I can process it if not. I know mapquest, google, etc have it because they include that sort of info in their routing, but I'm not sure if it is available to the public anywhere.