The Davis Square Community

I recall that there was some heated discussion about a posting. The OP had seen a bus whose front sign was flashing "Call MBTA Police at xxx-xxxx." Unfortunately, the OP couldn't remember the number and so called the Somerville police at their business number. The person answering the phone said to hang up and dial 911, and the OP found this to be rude or something, eventually leading to LJ drama.

The background that probably isn't known to ordinary people but is well-known to police and other emergency-response folks is that 911 does not simply route you to the local police department. There's a whole specialized infrastructure behind 911. (I know this because I worked in VoIP for years and had contact with the "emergency dispatch" community/industry.) Your call doesn't go to the local police department, but rather a specialized dispatcher who is trained to know how to route your particular problem to the emergency service that can deal with it -- fire, police, ambulance, etc.

The 911 system tells the dispatcher where you are -- there's a complete database of the physical locations of all landlines and the cellphone system uses various tricks to locate you within 100 meters (IIRC). So the 911 dispatcher knows where you are -- even if you don't.

Calls to the 911 system are prioritized. In the old days, special wires were reserved for 911 calls, and even if the ordinary lines were overloaded, 911 calls would get through. These days the systems may be more sophisticated, but it's still set up that ordinary calls can't block 911 calls.

The point being, if the problem needs to be dealt with now, call 911 to maximize the chances of a "successful outcome". Other numbers don't work nearly as well.