http://ir.atmel.com/releasedetail.cfm?ReleaseID=665225

Where Atmel announced a new transponder chip & microcontroller, which do, indeed, use 128-bit AES. This is from 2012 though, so I'm not sure how widely adopted this particular chip is, or if other, older chips are in widespread use that are 128-bit AES.

But even if everybody is using 128-bit AES, all that means is that the actual encryption itself is probably essentially unbreakable. But, as well all know, cryptographic systems are more than just the raw crypto algorithm. All sorts of systems which use crypto are eventually found to be insecure, so this whole thing should still come as little surprise (well, to people like us anyway. To the average cop, maybe this all sounds like black magic).