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What Is an Evidential Breathalyzer?

Breanna Davis
Updated

 

You'll see "evidential" on professional breathalyzers like the BACtrack Eclipse. Here's what it actually means, and what it doesn't.

The two DOT standards

The U.S. Department of Transportation sets performance standards for breath alcohol testers, and NHTSA (the National Highway Traffic Safety Administration) puts devices through testing against them. The ones that pass earn a spot on a public Conforming Products List. There are two standards, and they're not the same.

  • An Alcohol Screening Device (ASD) tells you whether alcohol is present in the breath. That's genuinely useful, and it's a real standard, but it's the lower bar.
  • An Evidential Breath Testing (EBT) device has to go further. It has to measure how much alcohol is in the breath, accurately enough to be used as evidence. It's the toughest accuracy standard the DOT sets for a portable breath tester, and far fewer devices clear it.

"Conforms," not "approved"

When a device passes testing, the correct phrase is that it conforms to the DOT's standards and is listed on NHTSA's Conforming Products List. We use “conforms,” not “approved,” for two reasons: (1) that’s the terminology used by the federal program, and (2) “approved” can imply broader regulatory endorsement or legal admissibility.

The BACtrack Eclipse was tested by the DOT, met the EBT standards, and is on the Conforming Products List. Most breathalyzers only reach the ASD standard. The Eclipse meets the higher one.

To pass, a device has to prove its accuracy and precision at multiple alcohol levels, reject interference from other substances, and hold that accuracy across a range of temperatures and conditions. The Eclipse cleared all of it.

Conforming isn't the same as courtroom-ready

This is the part people misunderstand. A conforming device is accurate enough for evidential use, but that alone does not make a reading usable as legal evidence.

Using a breath alcohol result as evidence (in a DOT-regulated workplace test, say, or a legal proceeding) takes more than the right device. Federal rules under 49 CFR Part 40 also require:

  • A trained operator, known under DOT regulations as a Breath Alcohol Technician (BAT). 
  • Calibration on a regular schedule, using certified reference standards and established procedures. 
  • Documentation and recordkeeping of the test, the device, and the result. 

The device is the starting point. The trained operator, the calibration, and the records are what hold up under scrutiny.

What this means for you

The Eclipse is designed for personal and professional alcohol screening applications. Although it conforms to NHTSA’s EBT performance standards, BACtrack does not market the device as a standalone evidential testing system for legal proceedings or DOT-regulated alcohol testing programs. Formal evidential use may require additional procedures such as trained operators, scheduled calibration, documentation, chain-of-custody records, and compliance with jurisdiction-specific requirements. As a result, Eclipse readings are not intended to serve as standalone courtroom or legal evidence. 

Bottom line: the Eclipse conforms to NHTSA’s EBT testing standards, meeting rigorous federal requirements for accuracy, precision, and reliability. When you use an Eclipse, you’re getting readings from a device tested against some of the toughest performance standards applied to portable breath alcohol testers. 

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