A Texas legislator has filed a bill that would, in part, call for the state to replace vehicle inspection stickers with radio frequency identification (RFID) tags, otherwise known as transponders.
Those active RFIDs that you've pictured are relatively large compared to the sticker type passive RFIDs I'm thinking of.
Also, the active RFIDs cost in the 30$~50$ range vs. 50 cents for the passive. Granted, no price is too high for Government when they are paying with other peoples money.