Breath Alcohol Content Screening: BAC in North Carolina

North Carolina regulates alcohol screening under a set of rules involving technical standards, operational procedures, and legal provisions that govern how breath tests are administered and how results may be used in criminal proceedings. Officers rely on portable breath alcohol content screening devices (sometimes referred to as a “PBT” or “breathalyzer”) in the field to detect whether a driver has consumed alcohol. Breath testing devices involve following standards set by the Department of Health and Human Services (DHHS) and must be approved by the Forensic Tests for Alcohol Branch.

This post serves as a primer for some of the important aspects of the North Carolina administrative and statutory framework for alcohol screening devices. It explains the significance of regulations like 10A NCAC 41B .0503 and 10A NCAC 41B .0502, along with the NC DWI laws, to show how our state manages breath sampling and the related BAC results. If you have questions about the specifics of your unique legal matter, or if you want to discuss the role of screening devices in your case, give us a ring or text the Powers Law Firm at 704-342-4357.  You may also email Bill Powers directly at Bill@CarolinaAttorneys.com.

Below is a synopsis of the topics covered in this article. Each entry links to a section that describes how North Carolina’s framework addresses the approval and calibration of the PBT and provides a big-picture perspective behind the use of approved alcohol screening devices.

Table of Contents

1. North Carolina’s Regulatory Structure
2. Approved Screening Devices
3. Periodic Calibration and Verification
4. Screening Test Procedures in North Carolina
5. Statutory Context: G.S. 20-16.3 and Implied-Consent Offenses
6. On-the-Scene Encounters and Checking Stations
7. Recordkeeping and Documentation Requirements
8. Distinguishing Screening from Evidentiary Testing
9. Practical Considerations for Drivers and Law Enforcement
10. Moving Forward with Legal Guidance

1. North Carolina’s Regulatory Structure

The system that governs alcohol screening in North Carolina draws upon multiple sources of authority. The Department of Health and Human Services maintains regulations through the Forensic Tests for Alcohol Branch, which evaluates and approves devices. The North Carolina Administrative Code (NCAC) spells out rules on how devices must be calibrated, how logs are kept, and how tests are administered.

• Administrative Code Provisions:
  10A NCAC 41B .0502 and .0503 define which devices are approved and outline how calibration is verified. They reference factors like the frequency of verification, acceptable methods for simulator solutions, and expiration dates for gas canisters. These administrative code provisions also detail logs that must be maintained, highlighting the importance of consistent recordkeeping.
• Departmental Oversight:
  The Forensic Tests for Alcohol Branch conducts evaluations intended to ensure portable breath test (PBT) screening devices meet minimum standards for accuracy, stability, reliability, and cost-effectiveness. Approval does not end with the device type; it also includes rules governing usage and maintenance. As such, law enforcement agencies are expected to follow operational instructions.

This structure helps create a framework where law enforcement officers may rely on portable screening devices in the field, most commonly associated with making the “arrest decision” when determining whether probable cause to arrest exists. To comply with these regulations, agencies should abide by calibration and usage requirements.

2. Approved Screening Devices

The state approves specific makes and models of alcohol screening devices through 10A NCAC 41B .0503. Examples include:

• Alco-Sensor (various versions), manufactured by Intoximeters, Inc.
• S-D2 and S-D5, manufactured by CMI, Inc.
• Lifeloc FC10, manufactured by Lifeloc Technologies, Inc.
• Alcovisor Mercury, manufactured by PAS International.
• Intoxilyzer 500, manufactured by CMI, Inc.

Each approved device listed has gone through some minimal evaluation process. The Forensic Tests for Alcohol Branch checks factors such as the reading display (two-digit or three-digit), serial number ranges (for enhanced devices), and the manufacturer’s specifications. This means that officers who use one of these models for roadside PBTs are using equipment the state has determined acceptable.

When an officer administers a breath test using one of these approved devices, the officer’s agency is expected to maintain logs and verify calibration at least once every 30 days. If the device is used but not properly calibrated, the reported result could be questioned in a legal dispute. Such such, agencies typically track compliance to confirm the device’s calibration is up to date.

3. Periodic Calibration and Verification

North Carolina’s administrative rules mandate calibration checks for approved screening devices at intervals not exceeding 30 days. This verification uses one of two methods:

1. Alcoholic Breath Simulator:
   A device that passes a known concentration of alcohol vapor through the PBT. The solution inside the simulator should be replaced every 30 days or after 25 calibration tests, whichever occurs sooner.
2. Ethanol Gas Canister:
   A canister containing a controlled amount of ethanol vapor. It should not be used beyond the expiration date printed on the canister. Operators document the canister switch or calibration checks in a “test canister log.”

If verification is overlooked or if logs are missing, that could be problematic for the state. The premise is that a device could drift out of calibration, especially if not maintained according to the Administrative Code. Routine calibration supports consistent, reliable readings over time. It’s important to note, relative to DUI charges in North Carolina, the numerical reading (the BAC) is not admissible for substantive evidence of impairment.  The PBT may be utilized to determine whether a breath sample is either “positive” or “negative” for alcohol.  As a practical matter, police officers, NC Highway Patrol troopers, and other law enforcement officers not only rely on the reported BAC but also record the same in their narratives and police reports.

4. Screening Test Procedures in North Carolina

Rules like 10A NCAC 41B .0502 explain how an officer should administer a breath screening test. Although the rule contains specific language, key points include:

• The officer is expected to confirm the driver has removed any food, drink, gum, or foreign substances from the mouth.
• The driver may be tested immediately, unless the driver indicates recent consumption of alcohol. If an initial result reads 0.08 or higher, the officer is told to wait five minutes and administer another test. A substantially lower second reading may prompt the officer to disregard the first PBT result.
• The officer may request multiple tests as needed.
• The device must be approved by DHHS, and the officer must follow the operational instructions from the Forensic Tests for Alcohol Branch.

Adherence to these procedures helps bolster the reliability of a roadside test. If an officer fails to observe the waiting period or forgets to clear the mouth of substances, that omission could lead to a challenge regarding the test’s reliability.

5. Statutory Context: G.S. 20-16.3 and Implied-Consent Offenses

G.S. 20-16.3 outlines when an officer can request a driver to submit to a breath screening. The statute explains:

• An officer must have reasonable suspicion or articulable suspicion that the driver has violated an implied-consent offense. This suspicion can arise from a traffic violation, an accident, or other factors indicating the driver has consumed alcohol.
• Requesting a breath test under these grounds does not amount to an arrest. It is considered a preliminary investigative step.
• The device and its manner of use should conform to DHHS approval.

This means an officer who observes signs of alcohol use can deploy a roadside device (PBT) if it is on the approved list and properly calibrated. A positive result might lead to further investigation, including an evidentiary test later. A negative reading for alcohol might reduce the probability of arrest unless other facts suggest impairment by a different substance or other suspicious circumstances.

6. On-the-Scene Encounters and Checking Stations

Officers use portable devices during routine patrol stops, after collisions, or at checking stations (roadblocks) authorized under N.C.G.S. 20-16.3A. These checkpoints must follow policies that specify a pattern for stopping vehicles, helping ensure no officer has unchecked discretion over whom to stop or test.

• Written Policy: Agencies typically have a document explaining how officers determine which vehicles are pulled over and under what conditions a breath test is administered. While a best practice, written policies are not required in every instance. As is the case with many criminal laws, there are exceptions to the general rule.
• Reasonable Suspicion: While there may be no observed violations of the NC Motor Vehicle Laws at a checkpoint, an officer still needs grounds to believe the driver has consumed alcohol before administering the test.

Portable Breath Tests (PBTs) at roadblocks can lead to additional investigative steps if the officer’s suspicion intensifies based on the test outcome and other indicators of impairment, such as the odor of alcohol, red glassy eyes, or slurred speech.

7. Recordkeeping and Documentation Requirements

Agencies using approved screening devices should keep logs of calibration checks. These logs, designed by the Forensic Tests for Alcohol Branch, record:

• Date of each check
• Device details (including serial number)
• Method (alcoholic breath simulator or ethanol gas canister)
• Information on when simulator solutions were changed or when gas canisters expired

Without these logs, it can be difficult to confirm a device’s proper calibration and reliability. The instructions do not specify a mandatory retention period beyond each agency’s policy, but failure to maintain logs could give defense counsel an avenue to challenge the validity of test results. The logs are intended to ensure consistent monitoring and help maintain transparency about the device’s condition.

8. Distinguishing Screening from Evidentiary Testing

A roadside screening device does not replace the evidentiary breath analyzer typically found in a law enforcement facility, intake facility, or local jail. Under the implied-consent laws (N.C.G.S. 20-16.2), an in-depth test (like an Intox EC/IR II) provides evidence for the prosecution of Driving While Impaired (DWI). Portable devices such as the Alco-Sensor FST generally offer preliminary information to guide an officer’s decision.

• Limited Admissibility: Screening results show the presence or absence of alcohol but are not used to prove a specific BAC in court, see  N.C.G.S. 20-16.3(d).
• Negative Results: If a roadside test indicates no alcohol, an officer might investigate other substances or consider medical explanations for any observed impairment.

By separating screening from evidentiary testing, North Carolina relegates the roadside PBT test to an initial assessment tool rather than the final proof of impairment. Blood testing and evidentiary breath tests on the EC/IR II are more reliable, less subject to operator errors and calibration issues, and are ordinarily admissible as evidence of impairment if they comport with the NCAC and statutory protocols.

9. Practical Considerations for Drivers and Law Enforcement

From a driver’s perspective, a roadside screening is a preliminary method for an officer to assess possible alcohol consumption. Refusal to take a screening test may become part of the officer’s decision on whether to investigate further, but it is not an implied-consent test that leads to an immediate license revocation for refusal. Put simply, refusing the AlcoSensor does not result in a license suspension.

From a law enforcement officer’s standpoint, portable screening devices can help streamline the investigative process when no alcohol is present. This potentially saves time for both the driver and the officer. However, strict adherence to calibration protocols and maintenance logs is essential to preserve the test’s credibility. Failure to document periodic checks could raise doubts about the reliability of the PBT device.

10. Moving Forward with Legal Guidance: The Powers Law Firm

The rules and statutes that shape North Carolina’s alcohol screening framework create a systematic approach for on-the-spot breath tests. Devices are evaluated for reliability; their calibration should be verified and documented in a test canister log. Still, no system is entirely free from errors. If questions come about—whether about device approval, the waiting period, or proper calibration of the PBT—experienced DUI lawyers consider the implication of the fact pattern, relative to the NC Administrative Code and general statutes.

Each scenario is unique. A defense attorney may want to review maintenance records, confirm calibration procedures, and assess whether the operator complied with mandatory wait times. The lawyer may think it important to confirm the officer had lawful grounds to request a screening in the first place. Understanding these rules can help in developing a defense strategy for DWI allegations and other charges involving alcohol.

If you have questions about the specifics of your legal matter, the legal team at Powers Law Firm is available for consultation. You may call or text 704-342-4357, or email Bill Powers at Bill@CarolinaAttorneys.com. By reviewing how North Carolina approves and calibrates PBT screening devices, along with the logs that support them, you and your attorney can gain a better grasp of whether the test was administered correctly—and how that might affect your defense. Call now to schedule a confidential consultation.