It's not like cops can pull you over for simple possession of weed in your glove box. They pull people over for a traffic infraction and then find the weed, illegal gun, etc.
I once looked up the arrest records in my local area. The number one reason for arrest was "driving without a license." (with no other infractions listed). I'm not saying that this was racial profiling, but I'm not denying that people with Hispanic last names accounted for the vast majority of these arrests. I am at least implying that it is a little suspicious and maybe requires a little more nuance and closer inspection.
Right. Generally, when somebody gets pulled over for a trivial violation and then something bigger is found during the stop, they only write a ticket for the bigger violation. Less paperwork that way and has the end result they were looking for.