During a minor car accident where no one is injured you can usually exchange the insurance information and drivers information and then make a police report later without having to call the police and wait for them.
Whenever I've gotten into minor fender benders or minor car accidents where only little damage was done and no one was hurt I would get the other drivers insurance information and name and address and then go to the police station and make out a police report their for the car accident.
In that case I don't need to waste the police time to come out to the minor car accident when they might be needing to get to another major accident or emergency.
If you want to then you can call the police and report the accident especially if the other driver doesn't want to work with you on the information.
But if they will work things out with you then you should just exchange information and then be on your way and then do the police report as well as do the insurance reports such as reporting the car accident to the insurance.
Or you can just wait until the insurance company is alerted of the car accident.