This may not be common knowledge to most people, though police department (and other municipal departments) require insurance policies to settle claims with people who allege wrongdoing. The most common wrongdoing though, is committed by police departments, and it is typically much cheaper for the department to settle with the insurance company and have them payout.
For most large departments, this isn't an issue though, as they don't have too many claims to deal with and their insurance company has no problem paying out their claims after they pay their monthly premiums. They also can self insure themselves, as they have large amounts of funding from their municipalities
For smaller departments though, they need to band together with other municipal departments (such as the surrounding town departments) to get insurance coverage. As the insurance company will only cover them if they're banded together and they spread out the risk.
Though this opens up an issue with these smaller departments though, as when these smaller departments are riddled with claims and have to settle multi-million dollar lawsuits -- they're stuck between a rock and a hard place as they're kicked out of their plan and are forced to shut down their police departments -- as the risk of operating is too much for them.
This is where Insurance companies come in to recommend / force change on a department to ensure that the department is running properly, and can operate under their insurance plan. This isn't common knowledge, but insurance companies are the reason for a large number of changes in law enforcement.
1. Men searching men, and women searching women (pat-down, limits liability and the chance of a lawsuit)
2. Strip searches only in individual events.
3. Rules of engagement
4. Increased community outreach.
5. Insurance companies can even help with when to fire an employee (if they're too much of a liability to the department)
https://www.npr.org/sections/money/2019/03/22/705914833/episode-901-bad-cops-are-expensivehttps://www.theatlantic.com/politics/archive/2017/06/insurance-companies-police/529833/