Here is a great 911 FAQ written by one of ANA’s members who has worked for the city.
Should I call 911?
If you have to ask, the answer is probably YES.
What do I call 911 for? Should I call 311 instead?
While the distinction in many cities is emergency versus non-emergency, in Chicago, it’s a bit different. In Chicago, if you want police/fire/ambulance wheels to roll, you need to call 911. If you want someone to do something in a few days (or weeks), call 311. If you want someone other than police/fire/ambulance, call 311. According to the City of Chicago, “You should call 911 if the incident you are reporting is in progress and the on-site presence of a police officer is necessary to help resolve the matter.”
But, I don’t know if I actually saw anything.
Please, allow the police department to do their job. That means providing them with as much information as possible. And that includes just telling them you saw something odd or out of place. Your call telling them about a suspicious van parked with someone in it in the alley may get combined with information about a burglary an hour later. You have one piece of information in a big puzzle. Please share it with the police by calling 911.
What if it’s just fireworks? Or a loud party?
Fireworks are against the law in Chicago. Depending on the time of day and the volume, a loud party may be breaking the law. Instead of trying to determine who is or is not breaking the law, please call 911 and let the police decide.
Will the police actually show up?
It depends. The police triage 911 calls, meaning they prioritize. A gunshot or a report of active domestic violence will receive a response much more quickly than a parking problem.
But I called and they didn’t show up!
Well, there are a couple of possibilities here. One is that they actually showed up. Sometimes police response occurs in an alley rather than on the street, or by way of an unmarked vehicle. Regardless, your call was logged. And that brings us to…
Are there enough police to respond?
Not if you don’t call. One of the primary factors determining police staffing levels is the number of 911 calls to which police must respond. In some neighborhoods in Chicago, when a person sees someone out of place, they not only call 911, but they call all their neighbors, who also call 911. As a result, that one sighting results in 5 or 10 911 calls. The city looks at this data and determines that the neighborhood needs significantly more police resources, based on the large number of 911 calls.
What will 911 ask me?
Details. If you are calling about a suspicious person, they are apt to ask you the height, clothing (including hat/cap), and race of the person. This information is important because it may allow the officers to identify the person even if they are a few blocks away from where they were when you called.
Do I have to leave my name?
You may remain anonymous when you call 911. (Simply tell them that you want to remain anonymous.) However, the police sometimes may wish to contact you for follow up or to clarify an aspect of your call, so you may wish to leave your name and a phone number or your address.
But, what if I don’t want to get anyone in trouble?
Lots of “neighbor issues,” such as loud parties, can be dealt with by neighbors communicating with other neighbors. If you’re comfortable talking to your neighbor about a problem, it’s the neighborly thing to do. If anyone’s safety is in question, though, please call 911 immediately.