The Role of the Expert in DUI Cases

The combination of stricter legislation and increasing scientific evidence that almost all drivers are impaired at .10 percent has led to an increase in the prosecution of accused drunk drivers.

Prosecutors and defense attorneys now have a special burden in the DUI/DWI arena. That is, the burden to understand basic scientific principles and concepts so that the direct and cross-examination of an expert can be most effective. Whenever an expert needs to be called, the attorney must be aware of the issues around the case and know enough about the science to head off statements and claims made by an expert that may not have a logical, scientific basis.

The expert has a burden as well: to give unbiased, informed opinions of the case. The role of the expert is not to take sides in litigation. The role of the expert is to supply knowledge and opinions about scientific concepts regarding the case, and to relay the information in a manner easily understood by the jury. The expert must be unbiased in the review of the case and the application of the science, and must strive to give fair and impartial opinions in court.

Our firm knows how to utilize experts in our clients' defenses as well as how to cross-examine experts brought forth by the prosecution. Contact our firm to learn more about whether an expert is necessary for your case.

The Expert's Qualifications

An expert must have qualifications that are adequate to perform a thorough review of the case. Administrative toxicologists who have limited hands-on experience should be cautious about rendering bench-level opinion. Many times it is the bench-level chemist who is fully aware of the inaccuracies of the instrument used for the analysis, or the errors that may occur during analysis. Toxicologists who have never used a particular breath testing machine must be cautious about giving expert testimony (aside from basic theory) on the field application of the machine.

Even experts with an advance degree, such as an M.D., must be cautious. The M.D. may be qualified to speak on pharmacology or toxicology general issues, but must be cautious in rendering opinions in areas he or she may not have fully explored, such as drugs of abuse, drug recognition examination, alcohol effects on driving, field sobriety tests, or laboratory instrumentation and interpretation.

The expert must keep current in the literature published in the field. The expert must belong to technical organizations that are focused on the areas of expertise being offered. Experts who have been in the field for several years should strive to publish papers in the field.

Contact Us

Timing is critical. Contact us to discuss your legal rights and options with one of the DUI lawyers at Shaffer & Engle Law Offices, LLC.

Learn more about expert witnesses on our Criminal Law Blog.