Washington State Radio Frequency Interference Defense

Electronic equipment in use in the area of a breath test may interfere with a breath test machine and cause it to report inaccurate results. This may also result in a false positive result. The breath test machine currently in use in Washington State has an antenna that is supposed to detect radio frequency interference, but it will not prevent a false positive or an inaccurate result if it is not attached properly.

Some devices that can interfere with the proper functioning of the breath test machine include:

• Refrigerators
• Air conditioners
• Police radios
• Cell phones
• Other electrical devices

Some of these devices may cause errors in breath test results if the breath test machine shares a power circuit with the other instrument, and some may interfere because they are in use too close to the machine. It is important to have an experienced and knowledgeable DUI attorney  conduct a thorough investigation if you do not believe your breath test report accurately reflects how much alcohol you actually drank. This investigation can help determine whether radio frequency interference or another outside factor may have influenced your test result. An experienced DUI attorney will be aware of the proper methods of conducting such an investigation, and will know how to interpret clues that point to a radio frequency interference or other defense.