The question, asked at a crucial time in DUI trial in Snohomish County by Attorney Brian Sullivan, expounded on the point the State had sought to obscure. The machine they alleged was so certainly accurate had a much larger margin of error – aka: confidence interval – then they were prepared to answer about. Was it plus or minus 6%? 10%? 25% or more?
Critical in any allegation of DUI is the allegation of BAC. But how accurate is the State’s evidence? Can it be flawed – both up and down? All experts seem to agree it can be. The key to success then in an over .08 breath test case then is explaining this critical fact to the jury.