Choose expert witnesses carefully when building DUI defense

When an individual is arrested for suspected DUI, there are a couple ways police officers can support a citation. One way is by administering an official breath test. If the result of such a test is 0.08 or above, an individual can be charged without needing to provide other evidence, provided the breath test was properly administered and accurately read.

Another way that officers can issue a citation for drunk driving is by collecting enough circumstantial evidence that the driver was under the influence of alcohol and that this impaired his or her ability to safely operate a vehicle. In this approach, officers rely on various observations, including field sobriety testing. One weakness in the latter approach is that officers’ observations are not always completely accurate. What looks to be intoxication may not necessarily be intoxication, at least in some cases. 

When prosecutors try DUI cases based on circumstantial evidence, defendants and their attorneys may bring in expert witnesses to help clarify what can reasonably be inferred from certain police observations. Such experts can be particularly helpful in cases with unique circumstances if they can cast reasonable doubt on officers’ conclusions.

A well known doctor who served as an expert witness in nine DUI trials in Pennsylvania was recently put on house arrest and probation after pleading no contest to perjury charges. According to prosecutors, he did not have the credentials he claimed to have.  Although the doctor did not admit guilt to the perjury charges, his case casts a bad light on expert witnesses that testify in such cases.   

The lesson here: when selecting an expert witness with your attorney, it is important to work with an individual who is reliable and fully qualified to testify in court about such important matters.

Source:, “DUI expert pleads no contest to perjury charges, gets house arrest and probation,” Matt Miller, April 8, 2014. 

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