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Radio Frequency Interference In Breathalyzers


As part of this blog, we have discussed that law enforcement generally uses Preliminary Alcohol Screening devices (breathalyzers) during the initial DUI investigation.  I have mentioned that the results of these tests can be wildly inaccurate, and in many instances have opportunities to be challenged. The issue of radio frequency interference has been raised on many levels to illustrate the susceptibility of the current units to inaccurate results.

The potential sources of radio frequency interference (RFI) within the law enforcement environment are numerous – for example, AM and FM radios, police station dispatchers, hand-held police transmitters, teletypes, and police radar units. Each of these may emit the kind of interference that could cause specific DUI breath alcohol test devices to render false results. It was then learned that the federal government (National Bureau of Standards) was testing for RFI sensitivity every type of breath testing device currently in use by law enforcement agencies in DUI investigations. The prosecution may counter the DUI defense attorney attack in a DUI trial by pointing out that the machine has an RFI detector. The problem with such detectors is that they are simply not reliable. First, as repeated tests have demonstrated, there is a segment of the frequency band to which the detector is essentially blind. If there is a source of interference from a device emitting electromagnetic waves in this frequency range, it will not be detected.

The post Radio Frequency Interference in breathalyzers appeared first on Law Offices of Taylor and Taylor - DUI Central.

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