[Yetiman]

In Wisconsin, as of last July (08') the state has stopped emissions testing on 2004 and older, testing OBD2 cars only as it's easy and cheap.
The reason ? Budget cuts. It costs too much money to test. Before that any cars 1968 and newer needed at least an initial test to get registered and than all cars under 20 years old needed annual testing.

(Note, emmissions testing was not state wide even by the old standards.Only the more heavily populated counties, about half the state required testing as it was too expensive to do state wide).

The high cost of enforcing higher standards might be the best thing we have going for the car hobby.