It is well established that driving a vehicle on public roadways is a privilege, not a right. That privilege can be granted or taken away by the state for a variety of reasons and each year police conduct hundreds of thousands traffic stops of one kind or another to enforce laws passed by cities or states.
In a 3 page APA formatted paper discuss the key elements that establish a traffic stop as legally defensible and professional.
Additonally, research, cite, and discuss case law that established the legality of individual traffic stops and traffic check points (such as a DUI checkpoint).