THIS IS PART OF A SERIES OF FILMS DESIGNED TO TRAIN NEW AND EXPERIENCED PROSECUTORS IN THE EFFECTIVE HANDLING AND INTRODUCTION OF EVIDENCE IN CRIMINAL TRIALS. IT BEGINS WITH THE POLICE OFFICER'S OBSERVATION OF ERRATIC DRIVING BEHAVIOR. THE IMPLIED CONSENT LAWS OF SOME STATES ARE NOTED. THE LEGAL BURDENS OF THIS PHASE -- THAT THE ARREST IS LEGAL, THAT THE OFFENDER IS ADVISED OF HIS RIGHTS, AND THAT ALL PROPER PROCEDURES ARE CARRIED OUT -- ARE ALSO EXAMINED. THE PROPER OPERATION OF THE BREATHALYZER, THE BASIC PRINCIPLES UPON WHICH IT WORKS, AND ESSENTIAL LEGAL PROCEDURES, SUCH AS ADVISING THE OFFENDER OF EXACTLY WHAT IS HAPPENING AT EACH STEP OF THE TEST ARE ILLUSTRATED IN A SIMULATED BREATH TEST OF A DRUNK DRIVER. THE FILM THEN SHOWS THE TRIAL AND THE TESTIMONY GIVEN BY THE ARRESTING OFFICER AND THE BREATHALYZER OPERATOR. IMPORTANT DETAILS, SUCH AS ESTABLISHING THE TIME OF ARREST AND OF THE BREATH TEST, ARE STRESSED. VARIATIONS BETWEEN STATES IN LAWS REGARDING EXPERT TESTIMONY IN SUCH CASES ARE NOTED. (VDA)