'It's taxis from now on'
Magistrate Nasha Banwari also acquitted him on an alternative charge of driving with a blood-alcohol level of 0.21 percent (the current maximum is 0.05).
Carstens was visibly relieved about the outcome of the case, which has dragged on since December 2010. He embraced his lawyer Hilton de la Harpe outside in the corridor afterwards and quipped: "It's taxis from now on."
Banwari said prosecutor Andi Hess had failed to prove beyond reasonable doubt that Carstens had been intoxicated to the extent that he was unable to drive with the required degree of care.
Carstens was arrested late at night in the Cape Town CBD in December 2010 after two police officers in a patrol vehicle noticed his Mercedes-Benz being driven erratically.
On the drunken driving charge, Banwari said the testimony of both officials had failed to impress the court, and they had not corroborated each other.
One had told the court the only transgression for which they had pulled him over was that he kept changing lanes without indicating. The other had said Carstens's demeanour at the time had been the same as during the court proceedings.
She said their testimony had been "so poor" the court was unable to draw any conclusion from it.
On the alternative charge, she said the blood analysis process was so flawed as to render the results unreliable. The analyst had failed to adhere to prescribed methods.
The analyst was subjected to intensive cross-examination, and had said she had conducted the process in the manner she had been trained.
She was however not even aware of the manufacturer's directions for the use of the equipment involved, Banwari said.
Another flaw was that the scanner used in the process had been used beyond its prescribed time limit.