That's just how police are in the US. Law enforcement jobs select for authoritarian and social dominant personalities, and any pre-hire screening that's done does not seem to address this.
I say that we need fewer better cops.
With the power they're given, education should be
at least as long & dedicated as for engineers or
doctors. And selection criteria should limit the
profession to only those capable of handling the
stress & abuse with equanimity & competence.
This would be achievable without increasing costs.
Costs could even decrease, if one includes such
things as payouts from lawsuits, & the damage
done to people they've abused or murdered.
Most of the problem appears to be with drivers
& passengers of cars. Minor traffic violations are
quite amenable to being automated.
Cops are particularly prone to drunk driving because
of the perception that they're above the law.
Every car operated by a cop, either personal or
on the job should be fitted with equipment to detect
DUI, & shut down if the driver is deemed unsafe.