Procedures for Taking Breath Samples

Procedures for Taking Breath Samples

Taking breath samples from drivers suspected of drunk driving is a common procedure used by police officers to determine blood alcohol content. However, there are specific protocols and legal requirements that must be followed for breath samples to be admissible in court. This article will provide an overview of breath testing procedures, issues that may impact test results, and legal considerations.

Preliminary Tests

Before requiring a driver to provide a breath sample, officers will typically conduct field sobriety tests first. These can include walking heel-to-toe in a straight line, standing on one leg, and following a moving object with the eyes. Poor performance on these tests provides reasonable suspicion for the officer to request a preliminary breath test (PBT) [1].

PBTs are small handheld devices that estimate the driver’s BAC. They serve as a quick screening tool, but the results are not admissible in court. If the PBT indicates impairment, the officer then has probable cause to arrest the driver and request an evidentiary breath test on a larger approved device[2].

Implied Consent Laws

Every state has implied consent laws stating that drivers automatically give consent to be tested if suspected of DUI. Refusing a breath test can result in license suspension, fines, and other penalties[3].

However, drivers do have the right to consult with an attorney beforehand if requested. Officers must allow a reasonable opportunity for a phone call, though they don’t have to delay the test for hours waiting for an attorney to arrive[4].

Breath Testing Devices

Evidentiary breath tests must be conducted on devices approved by the National Highway Traffic Safety Administration. Common models include the Intoxilyzer 5000 and the Draeger Alcotest devices.

These machines use infrared spectroscopy to measure alcohol content. The driver blows into a mouthpiece and the device calculates BAC based on the amount of infrared light absorbed.

Maintenance and Calibration

Breath test machines must be properly maintained and calibrated to ensure accuracy. Each state sets requirements for calibration frequency, often monthly or quarterly.

Certified technicians perform calibrations using ethanol-water solutions of known alcohol concentrations. Records must be kept to establish a calibration was done properly before and after each test.

Medical Conditions

Certain medical conditions like diabetes, acid reflux, and hypoglycemia can produce false BAC results. The driver should inform the officer of any conditions upfront so additional testing can be done if needed.

A separate blood draw is often required for drivers claiming a medical issue impacted their breath test. The blood can then be analyzed to directly measure blood alcohol levels.

Mouth Alcohol

As mentioned earlier, residual mouth alcohol from recent food and drink consumption can falsely elevate breath test results. Proper observation by the officer minimizes this risk.

However, dental work and improper rinsing of the mouth can also introduce alcohol. In these cases, the driver should be monitored for at least 20 minutes after rinsing before the test.

Radio Frequency Interference

Radio frequency waves emitted by cell phones, police radios, and other devices can potentially interfere with older breath testing machines. Newer devices have safeguards, but officers still should keep electronics away during testing.

If RFI is suspected, the driver can request the officer repeat the test away from the source of interference.