Bobby Armstrong drove into another car at 1:30 am. He was arrested for drunk driving. At 3:51 am the police took a blood sample which showed a blood alcohol level of .18, more then twice the legal level of .08. The Nevada Supreme Court decides if the state can prove his BAC at 1:30 based upon the result at 3:51. Is “retrograde extrapolation” reliable? Nevada v. Armstrong Podcast