Gullberg R G
Breath Test Section, Washington State Patrol, Seattle.
J Forensic Sci. 1990 Nov;35(6):1342-52.
Many jurisdictions have "per se" driving-while-intoxicated (DWI) status expressed in terms of a blood-alcohol concentration (BAC) standard (in grams per 100 mL or the equivalent). Since breath-alcohol (BrAC) analysis is typically employed to determine BAC, there is often challenge to the use of an assumed 2100:1 conversion ratio. This concern may be relevant in light of considerable data that show a low percentage of cases in which BrAC greater than BAC, and this concern increases when the BrAC is used to predict BAC in the context of "per se" legislation. Probability theory provides a basis for estimating the likelihood of an individual having a BrAC greater than or equal to g/210 L with a corresponding BAC less than 0.10 g/100 mL. Actual field data from the state of Wisconsin (n = 404) were evaluated to determine the probability of this occurrence. The probability for this occurrence involves the multiplication law for independent events. The computed probability from the data was 0.018. The actual number of occurrences where BrAC greater than or equal to 0.10 g/210 L and BAC less than 0.10 g/100 mL was 5, resulting in a probability of 0.012. The concern of having BrAC greater than BAC at the critical "per se" level has a very low probability of occurrence, which thus supports the reasonableness of "per se" DWI legislation based upon a blood-alcohol standard determined by breath-alcohol analysis.
许多司法管辖区都有以血液酒精浓度（BAC）标准（每100毫升克数或等效单位）表示的“绝对”酒后驾车（DWI）状态。由于通常采用呼气酒精（BrAC）分析来确定BAC，因此使用假定的2100:1转换率常常受到质疑。鉴于大量数据表明BrAC大于BAC的情况所占比例较低，这一担忧可能是相关的，而当在“绝对”立法的背景下使用BrAC来预测BAC时，这种担忧会加剧。概率论为估计个体BrAC大于或等于g/210 L且相应BAC小于0.10 g/100 mL的可能性提供了基础。对来自威斯康星州的实际现场数据（n = 404）进行了评估，以确定这种情况发生的概率。这种情况发生的概率涉及独立事件的乘法法则。根据数据计算出的概率为0.018。BrAC大于或等于0.10 g/210 L且BAC小于0.10 g/100 mL的实际发生次数为5次，概率为0.012。在关键的“绝对”水平上BrAC大于BAC的担忧发生的可能性非常低，因此这支持了基于呼气酒精分析确定的血液酒精标准的“绝对”DWI立法的合理性。
