Laws are just a consequence of an actual cultural change, and can only succeed (and not precede) the conversion of hearts and minds. Voting and democracy should not become a device to placate the dissatisfied masses into silence, make them lineup for ballot, to choose a lesser evil who, in most likelihood, will turn out to be a egotistical power-seeker. We shouldn't conflate voting with "will of the people."
mandatory body cams rolling at all times unless they are in a bathroom.
turning off or a malfunctioning camera during the act of a police brutality event immediately pierces the qualified immunity defense and they are tried as citizens.
have an outside investigative body that has zero ties to the police department investigate any reports of abuse.
have another outside investigative body that has zero ties to the police department randomly sampling police stop footage to see if there are any instances of impropriety.
I am sure this list is non-exhaustive but it's a start. also, while we are here, fix the issue of civil asset forfeiture. the clear "we get to take your money because it looks suspicious and then keep it for the police department" is a huge conflict of interest.
[0] https://en.wikipedia.org/wiki/Quis_custodiet_ipsos_custodes%...