Roadside alcohol screening tests in North Carolina DWI investigations
What a portable screening device can establish, what the numerical result cannot prove at trial, and how refusal is treated.
Screening is different from evidential breath testing
A roadside alcohol screening device—sometimes called a portable breath test or PBT—is used during the investigation before arrest. It is not the same as the Intox EC/IR II chemical analysis generally administered after arrest.
Under G.S. 20-16.3, officers may request a screening test when they have reasonable grounds to believe a driver consumed alcohol and committed a moving violation or was involved in a crash. Approved devices and trained operation are required.
What may be admitted
The statute permits evidence of whether the screening test was positive or negative and whether the person refused. The actual numerical reading from the screening device is not admissible to prove a specific alcohol concentration. That distinction is important when an old report, witness or page treats a roadside number as equivalent to an evidential breath result.
Review points
A case review may include the approved-device status, operator training, observation of use, device maintenance where relevant, timing, multiple samples, surrounding field-test evidence and what the officer claimed the screening result established.
Frequently asked questions
Can the prosecutor tell the jury the exact roadside number?
The statute does not permit the screening number to prove a particular alcohol concentration. Other limited uses and the surrounding evidence require case-specific analysis.
Is a portable device the same as the Intox EC/IR II?
No. The portable device is a roadside screening tool; the Intox EC/IR II is an evidential breath-testing instrument used under separate procedures.
Can refusal be considered?
Yes. North Carolina law permits the fact of refusal to be used in evaluating reasonable grounds.