It used to be a higher percentage, I believe 50% spread over a 2 year period. So few people were being caught that they lowered the percentage to 25%. Maybe the positive hits are up since so many states are legalizing marijuana use and they raised it.
That's exactly why they lowered the threshold for how many tests must be administered. The baseline was 10% of the entire population presumed to be doing drugs.........Doctors, truck drivers , policemen, steel workers, nurses, politicians, sanitation workers, judges,..........10% of each demographic was supposed to be using drugs.
The.....problem became evident when the truck driver demographic produced less than 1% of positive drug tests. Apparently,.....Drug Addicts don't apply at jobs where the average work week is 60-70 hours,...and you're expected to be "on-call", do physical labor, and work outside in the weather.........
The ATA pushed Congress to establish "rolling urinalysis collection points"............here in Penna. , they have Winnebagos,....doing random drug tests at roadside inspections. This took most of the cost of random drug tests away from the companies,...onto the Taxpayers,.....and alleviated the liability and burden for the trucking companies.......
The State Police.....hated....becoming "urinalysis collectors".........and balked at doing this function as..."demeaning" to a State Trooper.....No mention about how......"demeaning"....it was to the truck drivers......
The Entry-Level drug test to get hired in trucking pretty much screened out the very few "brain-damaged" drug users stupid enough to apply at a trucking company for work. Random tests by both State Police and Employers were producing less than 1% of positive tests.........It was a billion dollar boondoggle,....as far as the companies were concerned......Cut into profits needlessly...
Then comes the Great Driver Shortage of the past 5 years.........and companies lower their standards in an attempt to entice.....anybody, brain-damaged or otherwise,.....into driving a truck...
And,....Presto!......the positive drug tests started inching up closer to the 10% baseline....
I'm sure you're right that legalized Marijuana,...and opioid pain medication has something to do with the increase in required tests.....