I rarely arrest people when I find weed on them anymore. Prescription pills(not prescribed to them) seem to be the 2nd most prevalent drug found on people I arrest. I've only made a couple meth arrests, and coke is not that available where I live.
Heroin is the most hardcore IMO due to the addictability of it, users are hard to spot but always broke because they need it every day to function. Coke not so much, I consider it a recreational drug for the most part, users are hard to spot. Meth users end up killing them self and are easily spotted.
I think about 80% of the people I encounter on a daily basis have weed. I just write them misdemeanor citation, take their stash and paraphernalia. They can work it out with the courts.
if i was a cop i would just take peoples stashes smoke it on the job then pull someone over and be like "license and taco bell nigga!!!! raa