When small, adjacent cities each run their own emergency dispatch centers, it can be difficult to coordinate public safety on a regional level. It's also expensive.

But in the metro Boston area, some cities are teaming up to consolidate their emergency response centers. For the past several years, the cities of Somerville, Medford and Melrose have been working on a plan to create one regional dispatch center that will serve them all. The agreement is almost ready to be finalized.

How should cities determine minimum police staffing levels? In San Francisco, some city supervisors think it should be based on population. Others want to see it based on the police department's workload demand.