ArrivalStar, a patent licensing company that has filed multiple infringement lawsuits against public transit systems, took fire from two non-profit public interest groups this week. On Tuesday, the American Public Transportation Association (APTA) filed a suit that seeks to invalidate ArrivalStar patents related to systems that alert passengers to arriving buses and trains. And on Tuesday, the Electronic Frontier Foundation announced that it had convinced the Patent and Trademark Office to knock out all but two claims of a key ArrivalStar patent.

For anyone unfamiliar with ArrivalStar, this story that ran last spring on The Atlantic Cities website has some good background. A quick summary: The company does not make any products, but its Indiana law firm, Dowell Baker, has set up a dedicated phone account to track all of the public transit notification systems and cell phone apps that might infringe ArrivalStar patents.