Clinched Interstates

There's a neat new website that you can use to generate a map of all the Interstate highways you've been on. I should warn you that preparing the file to generate your map will probably take a while, unless you haven't done much travelling. My own map, along with state-by-state statistics, is here, or you can see a condensed version below, where the dark blue indicates the ones I've clinched.

There are a few unsigned "mystery Interstates" out there, like these ones in Puerto Rico. Click and scroll down to "additional designations" for something of an answer.