[x0x0]

You're misunderstanding reality. The simple fact is that these tests are not designed to detect drugs. They're designed to give the police a pretext to search you, whenever they wish to do so, while pretending to obey the law. How do we know this? If they were designed to detect drugs, the fact that they're very poor at doing so would be seen as a problem. It isn't. Therefore, they're designed for a different purpose.

See also breathalyzer, "drug detecting" dogs, field sobriety tests, visual estimation (without radar) of traffic speed, etc.

[fucking_tragedy]

The article itself mentions the drug tests used in the field coming up as positive for cocaine through just air exposure.

Here is another that confirms the same thing happens upon air exposure to certain methamphetamine and marijuana field tests[0].

Point is that this abysmal false positive rate is that it's too convenient and the incentives are too high when it comes to maintaining an inexpensive shield for officer error / instant probable cause compared to court costs.

[0] https://www.themarshallproject.org/2015/04/02/jolly-ranchers...