However it throws hundreds of people through the equally discriminatory criminal justice system, and allows car insurance companies to jack up rates. Functioning even more effectively as a tax on being different than regular cops do. It also creates a financial incentive for the government not to fix the underlying cause of the problem of speeding.
Wishing and hoping for people to be better than they are isn’t a solution. Just because traffic calming is more expensive, that’s not a reason to not do it. It is something that needs to be done if you want to break car dependency.