Eric
Each state sets its own regulations... . not necessarily the 2010 standards but those local laws the states feel they need to clean up the air... . But for the most part all the states that test are going to the latest OBDII technology where the equipment must be on the vehicle and functioning... CA is pushing the window on this... what we see in CA will follow with the the rest of the country... .
Let me add that CA has asked that the computer in the cab of a class 8 truck (semi) interface with all the transmissions, engines, ABS and ABS on all the trailers on the road, and now their talking about environmental controls on the diesel refer units on trailers...
So that a state inspector, or a mechanic can connect to one data port in the cab of the truck and look at the reefer unit on the trailer, look at the transmission shift points, and the ABS... .
So you have at least 3 manufactures of ABS on trailers, 3 manufactures of reefer units, 4 good engine manufactures plus the computer controls in the cab of a truck... . you pull into an inspection station in CA and they want to see all of this data... and for trucks it all must work to pass the safety inspection... huge, really huge issues here...