Even if you are involved in a minor collision, you should still call the police.
Although in some jurisdictions the police don't respond to fender benders unless there's an injury or an unmoveable car blocking a thoroughfare, it's still a good idea to call them. It may seem unnecessary or time-consuming to do so, but they can provide a valuable resource. Even if the police do not create an official accident report (which in small collisions they may not be required to do), they can still create an incident report. This will help you if you are not at fault and the other party's insurance company is contesting liability or their insured is making false statements. They may also interview witnesses, and record details such as the time and place of the accident, license numbers and descriptions of cars, and names and addresses of the drivers and owners of each vehicle. This information may prove useful in the settlement process. Write down the name and badge number of the investigating officer, the name of the agency he or she represents, the name of the intersection where the accident occurred, and the number of the police report. This information will make it easier if you or your insurance company must contact the police to request a copy of the report.
Finally, a police officer can also cite the at fault driver if they believe they have committed a traffic violation. This can also help when the insurance company is investigating fault.