What a DUI Forensic Expert Does
Test results come with pages of logs, methods and quality control data. A DUI forensic expert reads those records and explains what they show. The expert may testify in court or simply help a lawyer understand the evidence.
However, experts do not decide cases. Instead they give opinions based on the records and their training.
Breath Test Reviews
For breath tests, an expert first looks at the instrument and the procedure. California rules in Title 17 section 1221.2 set the standards. They require two samples that agree within 0.02, regular accuracy checks and trained operators.
Then the expert compares the records with those rules. The article on breathalyzer calibration records lists the documents involved.
Blood Test Reviews
Blood reviews, by contrast, focus on the sample and the lab method. So an expert checks who drew the blood, how it was stored and how the lab tested it. Vehicle Code section 23158 lists who may draw blood, and it allows the person or a lawyer to obtain full information about the test.
The guide on DUI blood sample handling explains those records in more detail.
Timing Questions for a DUI Forensic Expert
Timing often sits at the center of a review. When did drinking stop, when did driving stop and when did each test happen? An expert may use that timeline to discuss whether a level was rising or falling.
The article on rising blood alcohol DUI questions covers that theory. Even so, the expert still needs reliable times from receipts, phone records or witnesses, since an opinion built on guesses carries little weight.
What an Expert Cannot Do
A DUI forensic expert cannot promise an outcome. Some records support the result, and an honest expert will say so. Also, an opinion depends on accurate facts from the person, so a hidden fact can undo it.
- Opinions rest on the records provided
- Missing records limit any review
- Courts decide what weight an opinion gets
Finding and Paying an Expert
A defense lawyer usually selects and retains the expert, because the lawyer knows which questions the case raises. The person typically pays the fee, and fees vary. For people with appointed counsel, the lawyer can explain how expert costs work in that setting.
Before that, ask the lawyer what records the expert will need first. Then gather them early, since some records take time to obtain. The guide on DUI criminal discovery explains that process.