Carolina Criminal Defense & DUI Lawyer Updates
Witnesses with specialized knowledge beyond that of a jury may in appropriate circumstances provide “expert testimony” in North Carolina. DWI (Driving While Impaired) charges in North Carolina regularly include evidence like breathalyzer results, blood
tests, and standardized field sobriety tests.
Given the scientific, forensic, and at times highly technical aspects of impaired driving cases, testimony may include qualification in court of expert witnesses and consideration of NC Rule of Evidence 702 (the rule governing experts and expert testimony). In some circumstances, the formal process of qualification is not required if the police officer is certified by the State of North Carolina as a DRE – Drug Recognition Expert. It can, frankly, prove to be a complicated area of law.
At Powers Law Firm, our attorneys understand the impact that credible experts can have in DWI trials and how critical it is to get reliable evidence before the finder of fact. That may entail both challenging the State’s attempts to tender a police officer as an “expert” and introducing a defense expert to counter the conclusion of the State’s witness and their expert testimony.
and medical conditions that could affect impairment assessments. This article examines the different types of experts used in North Carolina DWI cases, how courts determine whether their testimony is admissible under Rule 702, and what legal considerations apply when presenting expert evidence in court.
Department of Transportation – Division of Motor Vehicles (DMV) may move forward with revoking your license for failing to submit to breath and/or blood testing. 
technical procedures—such as chemical breath tests, blood alcohol analyses, and field sobriety testing—that lay jurors or even judges may not fully understand. An expert witness, properly qualified and admitted, can provide insight into such complex matters both for the prosecution and the defense.
blood testing in a DWI case. Law enforcement may suspect drug involvement, or the driver may be unable (or unwilling) to provide a valid breath sample on an approved device. DUI fatalities tend to involve blood testing, as it the more accurate method to confirm the different possible sources of impairment and the respective concentrations of each.
preliminary roadside screening with a handheld device, the real focal point often comes from the Intoximeter EC/IR II machine. This desktop breath-testing device measures deep-lung air and generates an official reading that prosecutors regularly use as evidence at trial.
(SFSTs) to gauge whether enough evidence exists for an arrest or further chemical testing. Roadside dexterity tests—commonly the Horizontal Gaze Nystagmus (HGN) test, the Walk-and-Turn test, and the One-Leg Stand test—remain a subject of debate. Questions arise about whether these tests are truly “standardized,” whether they reliably they measure impairment or are overly subjective, and how courts treat SFSTs as evidence.
screening at the roadside and an evidentiary test under the state’s implied consent laws. These procedures are guided by statutes like G.S. 20-16.2, which defines the expectations placed on a driver once probable cause is established. Although both tests relate to detecting alcohol, they serve different functions and carry different legal consequences.
license violations and to enforce the “drunk driving” (impaired driving) laws. The process must follow certain constitutional and statutory guidelines to avoid arbitrary or discriminatory stops.
circumstances, raise doubt about whether a reported BAC reflects the true breath alcohol content.