The rest are automatic, such as clicking a pre-configured link or having the browser execute request within a web page (for example, requests to call images and additional content from third party sites).
If you need more time, you can request an additional four month extension by filing federal form 4868, Application for Automatic Extension of Time To File U.S. Individual Income Tax Return (downloads as a pdf) by June 15.
Documents obtained through a Freedom of Information Act request and released Tuesday by the Electronic Privacy Information Center (EPIC) catalogue just how pervasive automatic license plate readers have become at the Mexican and Canadian borders, with cameras placed in dozens of U.S. cities each capturing images of millions or tens of millions of plates a year.