Issues with DWI Breath Testing:
Radio Frequency Interference
Limitations of Breath Testing in DWI Criminal Defense
In reviewing videotapes of my client’s DWI arrests I often see cell phones being used in the “intox room” as a DWI breath test is being administered. Law enforcement is aware of the issues arising from radio frequency interference in DWI breath test machines. The problem is that cell phones create radio waves, and these waves can interfere with the breath test. These issues have been documented since the 1980’s, but breath test operators do not follow the best practices and their mistakes are often not videotaped. A skilled DWI Lawyer will notice these issues and effectively communicate the importance of these issues to a jury.
Today cell phones are ubiquitous. There are often two cell phones present during a DWI investigation: one belonging to the officer making the DWI arrest; and the person being accused of DWI. And it is not unusual to see them in and around the DWI breath testing equipment. The prohibition against using portable radio transmitters, including cell phones, is grounded in well-known limitations in infrared breath testing technology.
The breath test machine used in Texas, Intoxilyzer 5000, has a detector for RFI. When the detector is working properly the breath test machine will not provide a breath alcohol reading when a threshold amount of RFI is present. Instead the machine should provide an “error message” stating that RFI is present and a reading cannot be obtained. The obvious issues arise when: (1) there is RFI present but not enough to trigger an error message; and (2) the detector fails (as any machine part will) and RFI is not detected. The problem with these detectors is that they are not predictable. It is impossible in many cases to determine whether or to what extent any particular breath test was tainted. The machine does not produce a reading of RFI and there is no independent detector present. So, the RFI present at a DWI breath test is not recorded for evaluation of the machine’s reading. This information that impacts the reliability of the DWI breath test is not available for you or a jury to view and consider later. People lose their freedom and are branded for life, and significant evidence regarding performance of the DWI breath test machine is not recorded or presented to juries.
This situation can best be understood if you think about trying to tune into a radio station with an old fashioned portable radio. It is important for the antenna of the radio to be oriented in the right position to receive the desired station. Thus, even though the RFI detector may be capable of sensing some RFI, the electronic circuitry of the particular breath testing machine could possibly be located in a position that it will not pick up the existing radio waves. We’re all aware of the multiple competing networks for cell phones. Additionally, the handheld radios of police officers are sending and receiving radio wave all around the DWI breath test machine.
RFI is one of the many reasons DWI Defense Attorney Cody L. Cofer advises people, “DO NOT BLOW.” If you have, it does not mean the government has a slam dunk case against you. A breath alcohol result is not an automatic conviction. However, if the reading for your DWI breath test is over 0.08 then you definitely need the help of an experienced, skilled, and knowledgeable Fort Worth DWI Defense Attorney. Call Cody Cofer today to talk over the facts of you case. He provides free initial consultations. Tarrant County has aggressive DWI prosecuting guidelines. In many respects the Tarrant County District Attorney’s Office is a leader in DWI prosecution. You need a DWI Defense Attorney that is capable of fighting your DWI Case. Cody Cofer is a former prosecutor and skilled DWI Defense Lawyer. Visit his downtown Fort Worth office to speak with a Criminal Defense Attorney for your DWI case.
DWI Defense Attorney (817) 810-9395
