A police radio call is made when the someone calls police asking for help. Sometimes they're the victim of a crime, or sometimes they're the witness to a crime.
And sometimes, there isn't any crime, it's just some nut calling in, but the Police have to go to find out if there is a problem.
When you're on patrol in a cruiser, the dispatcher will assign you to a call if you're not already assigned to one. Obviously, some calls that are received by the public are of more importance than others.
A shots fired call, for example, is clearly much more important than a dispute between two neighbors calling about an apple tree that is too close to the dividing fence, and dropping it's fruit in the neighbors yard. (Believe me, there are some dumb, childish people who actually call Police over stuff like this. If you get on the job, you'll unfortunately get to meet them)
The shooting will get dispatched before the "apple people", as it's of much higher priority.
The apple call will get placed into pending and when there are available officers, the apple call will eventually get dispatched. It could wait for a very long time depending on the priority levels of the existing police radio calls as well as availability of officers.
There are still members of the public who believe that calls get dispatched in sequence, or on a "first call, first serve" basis. They will get angry when you arrive on scene after 8-10 hours of waiting.
But hey, if it's been a busy night with high priority calls, and you've been rushing from one dispatched call to another, and it's taken you 8 hours to get to them. So be it.
Explain to them how it all works. Ask them if they think their fruit fiasco is more important than an abduction call.
That will usually settle them down. If it doesn't, just pick up a couple apples and hurl them right through the living room window. Just kidding.
If you are one of these "apple people types" and feel that I am being insensitive and not understanding....I couldn't really care.
I've been to enough of your calls and, quite frankly, I wish you would interact with your neighbors like adults, no matter what the issue, whether it be an apple tree, fence line, sitting on the porch at night, parking your car on the street too long etc etc etc.....
All Police departments use a call priority sequencing to differentiate calls. Some departments will be a little different, but this will give you a general idea on how police radio calls get prioritized:
Priority 1 calls- Emergency calls where it is believed that there is an immediate threat to life
Priority 2 calls- Emergency calls where it is believed that there may be a possibility of major property damage
Priority 3 calls- Calls which require immediate attention, but there is no risk of physical danger posed or significant damage to property.
There are many more priority levels, and sequencing continues down from urgent to least pressing in nature.