The new health insurance agreement that cuts spending by $28 million over four years demonstrates the good relationship between the city of Brockton and its 17 public employee unions. But critics say the city could have saved more if it had taken advantage of a new state law that increases communities’ ability to set health benefits.

The 2011 Municipal Health Insurance Reform Act gives cities and towns the option of changing the health care plans of public employee unions legislatively, without traditional collective bargaining.