A police office can make a traffic stop if he or she has a reasonable, articulable suspicion that you are committing a crime or traffic violation.  For example, for DUI, an officer may state that he observed you weaving and driving erratically.  An officer cannot use discriminatory factors such a race to meet the reasonableness requirements.  An officer’s failure to articulate a reasonable suspicion for pulling you over could lead to suppression of evidence or ultimately dismissal of your case.