When you have been drinking, flashing red lights in the rear-view mirror can induce panic.  Many people presume they will be arrested and convicted of DUI because they lack experience dealing with the criminal court system.  This inexperience promotes the belief that a DUI arrest along with failed field sobriety and breath tests mean that a conviction is inevitable.  This misguided but understandable misconception is promoted by the belief that DUI investigations are based on reliable science.  As a practical matter, breath test results frequently are inaccurate for a wide variety of reasons.