The Atlanta Journal Constitution reports that Gwinnett County Commission Chairman Charles Bannister has been arrested for DUI.  There is an interesting twist to this story.

According to the arresting officer, Mr. Bannister failed three field tests for sobriety, his restaurant bill showed purchases of 5 Bud Light beers + a half pitcher of beer, and he reportedly stated to the officer “I can’t believe this is all over one or two beers.”  Mr. Bannister was then given a breath test – which registered 0.00!

A blood test was later administered and the results have not been made  public.

Assuming that Mr. Bannister did consume some alcohol, the breath test (we can assume this was a  Intoxilyzer), the equipment used was clearly faulty.  In this case, the faulty equipment benefits the defendant but how often might a faulty breath test machine come back with a false positive?

The point here is not to pass judgment on Mr. Bannister or the integrity of Gwinnett County law enforcement.  You can take from this episode that breath testing equipment can be very unreliable.  A blood test offers a much more accurate reading of your blood alcohol levels (although there are grounds to contest these numbers as well).