  With geographic message dissemination, connected vehicles can be served with
traffic information in their proximity, thereby positively impacting road
safety, traffic management, or routing. Since such messages are typically
relevant in a small geographic area, servers only distribute messages to
affected vehicles for efficiency reasons. One main challenge is to maintain
scalability of the server infrastructure when collecting location updates from
vehicles and determining the relevant group of vehicles when messages are
distributed to a geographic relevance area, while at the same time respecting
the individual user's privacy in accordance with legal regulations. In this
paper, we present a framework for geographic message dissemination following
the privacy-by-design and privacy-by-default principles, without having to
accept efficiency drawbacks compared to conventional server-client based
approaches.
