My father did this for a living. As others have already said, it is to protect agriculture. In the early 70’s they shut down most of the California inspection stations thinking all the new pesticides would do the job. It did not work out and they had to reopen them.
Thank you for taking the time and posting an examination.
What other state has these kind of stations? I live in a big agricultural area and there are no inspection stations anywhere in the Midwest. I’ve driven all over the US and have never encountered a station like this from the Atlantic to the Rockies.
What makes California so special that they are the only state in the contiguous 48 to have this sort of inspection?