Witness testimony can be critical to the outcome of a DUI case. Prosecutors will present witnesses who could derail your defense, including but limited to police officers, toxicologists, and eyewitnesses. The damaging effects of witness testimony can be curtailed by effective cross-examination techniques by your Roswell DUI defense attorney. Depending on the circumstances of your case, witness testimony can be the proverbial nail in the coffin if not effectively countered by your defense attorney. For this reason, it is critical that you hire an expert legal representative with years of experience when defending your DUI charge.

The ultimate goal of your Alpharetta DUI attorney is to discredit or impeach the prosecutor's witnesses. The defense may also present its own witnesses to contest the testimony and evidence presented by the prosecution or provide its own version of events.

How is Eyewitness Testimony Used in a DUI Case?

Passengers, bartenders, and other drivers are among those who may be called to testify. Although eyewitnesses do not benefit from the same inherent credibility and authority as officers, they can still convince the jury - if their testimony is compelling and factual. Such witnesses may be able to provide the court with information critical to a positive outcome in your case.

For example, another driver may testify that there was nothing unusual about your manner of driving when you were pulled over. A bartender could recount how he served you only two drinks and was able to carry on a perfectly normal conversation with you before you left and got in your car.

How is Expert Witness Testimony Used in a DUI Case? 

Expert witnesses are commonly recruited in DUI cases to testify on one or more aspects of the case, including chemical testing, field sobriety tests, accident reconstruction, and more. The puzzling part about expert testimony is that the prosecution and the defense usually present two experts in the exact same field, who provide totally contradictory opinions. A toxicologist for the defense may argue that the blood or breath test was invalid, due to any number of reasons (e.g., improperly calibrated breathalyzer, a fermented blood sample, an incorrect amount of blood collected, the subject being more sober at the time of arrest than the time a sample was taken).

Conversely, a toxicologist for the prosecution may argue that the blood or breath sample was, in their professional opinion, collected correctly and was an accurate reflection of the subject's BAC. These two experts are in the same field but offer contradictory opinions. This stands to confuse the jury. Therefore, what truly matters is how effectively each side presents their argument as well as their ability to raise doubt about the opposition's expert witness while bolstering the credibility of their own.

Some expert witnesses testify in court for a living. There is a financial incentive to what they do, and to some extent, there is a degree of 'confirmation bias' in the statements made by an expert witness. Confirmation bias is defined as "the tendency to interpret new evidence as confirmation of one's existing beliefs or theories."

For example, if an expert is called to testify (and paid) by the prosecution, whose sole endeavor is to win a conviction, the expert may be inclined to take the facts with which they are presented and purposefully construe them in favor of the prosecution's agenda. It has been argued that police too may exhibit some form of confirmation bias during DUI arrests. If one already suspects that someone was driving under the influence, they may be inclined to hone in on the evidence that confirms their preexisting assumption of that person's guilt.

What Happens When a Witness Takes the Stand in a DUI Case?

Like photographs, documents, medical reports and statements, witness testimony is just another type of evidence. However, because it is sourced by a human being, there is more room for bias and subjectivity. The process usually unfolds like so:

1. Witness is sworn in, taking an oath to speak truthfully.
2. The witness is directly examined by either the prosecutor or the defense attorney, whichever one presented the witness as evidence. The attorney poses questions to the witness to elicit answers that give information pertinent to the case and strengthen that side's position.
3. The opposing party asks questions of the witness during cross-examination. This is an opportunity for the opposing side to weaken the other party's position, discredit the witness, attack the witness' credibility or poke holes in his or her story.
4. The original side has another opportunity to ask questions of the witness, in an effort to offset any damage done during cross-examination.

The prosecution begins with its witnesses and the defense follows.

Strategies to Discredit the Testimony of A Witness in a DUI Case

• Witnesses are sequestered so they do not hear one another's testimony before they take the stand. An attorney may be able to discredit a witness by showing inconsistencies between the statements of two witnesses who are discussing the same event.
• Attack the witness' motivation for testifying.
• Suggest simple bias, such as individual bias against the suspect.
• Attack the evidence on which the witness is making his or her statements. Statements made on feeble evidence will seem less compelling.
• Question the witness' ability to remember the details of the case; imply his or her their statements are inaccurate.
• Show that the witness is not adequately trained to give reliable testimony.

Roswell Alpharetta DUI Lawyer

DUI trials and witness testimony are complex in nature; they can often become a battle of semantics. If you have been charged with DUI in Roswell Alpharetta, you will require the services of an attorney skilled in the techniques meant to discredit witness testimony. This is a nuanced area of law that requires experience and precision. Hiring a high caliber Roswell DUI attorney could be the single greatest credit to your defense and is essential in your fight against these charges. Contact a Roswell Alpharetta DUI attorney immediately for a free consultation.