Domestic violence, traffic stop, hate crimes, mental illness and vice Crime. Vice crimes are those that offend the morals of the community, such as prostitution and pornography.
Example of police discretion during a traffic stops. A patrol officer stops a car because the diver is driving with the lights off during a rain storm which is against the law. After the officer encounter the driver he checks his license and registration and noticed that the driver has not criminal record then he can decide whether to write a ticket