It is a crime in South Carolina to drive with a blood alcohol concentration (BAC) of .08 or more. This law targets and punishes the status of simply having a BAC at or above .08 with no regard to proof of impairment. However, while the State is not specifically required to prove impairment beyond a reasonable doubt in DUAC cases, they must prove that there was probable cause that the driver was materially and appreciably impaired in order to justify the arrest. Given the inability of the investigating officer to determine a driver's BAC at the roadside, the arrest must always be for the impairment based offense of DUI.
While the blood alcohol concentration is the heart of the State's case in a DUAC prosecution every aspect of the investigation is significant and must be tested. The law permits a jury to consider every aspect of the case when deciding whether to accept the result of the breath or blood test as proof beyond all reasonable doubt of the true blood alcohol concentration. South Carolina is not a "trial by machine" state. The prosecution has the very real burden of proving the accuracy and reliability of their evidence, not simply presenting a number from a machine.
The arresting officer has the option of changing the charge from DUI to DUAC after the driver's blood alcohol concentration has been determined from the analysis of a breath or blood sample. The law does not allow the prosecution of both charges out of the same arrest, an officer must chose to prosecute one charge or the other no later than 30 days before the trial date.
