In my experience in one of the few blue enclaves in an overwhelmingly red US state[1], selectively enforced laws are frequently used by local law enforcement as an instrument of discrimination against "undesirables".
As a straight, white, young adult male, I noticed a strong correlation between the frequency of "pretextual" traffic stops in neighboring counties and the then-current length of my hair.
Racial minorities have it much worse:
Before Brainard took office, employees of then Carmel[, Indiana]-based One Call, many of whom were minorities living outside of Carmel and working late into the night, complained of being pulled over by Carmel police.
The city’s solution, which [Carmel mayor] Brainard called “terrible,” was to give employees car tags so police knew they belonged there, implying that if you were Black and didn't work there, the assumption might be that you didn't belong there. There was, however, no systemic change within the police department to stop ticketing Black people passing through." [2]
As for marijuana possession,
In Indiana, all but 13 counties are above the national average for racial disparities [in marijuana arrests]. And while Marion County’s rate of disparity is below the national average, there seems to be an alarming trend for surrounding counties to have disproportionately high arrests of Black community members. For example, Hancock, Hamilton, Shelby and Boone counties, all donut counties, have a racial disparities rate of greater than 10x. [3]
[1] https://en.wikipedia.org/wiki/Indiana%27s_7th_congressional_...
[2] https://www.indystar.com/story/news/local/hamilton-county/ca...
[3] https://www.aclu-in.org/en/news/racial-disparities-indiana-m...