Cracking the DUI Code

There is a controversy brewing in how law enforcement makes cases for driving under the influence, and that controversy is coming to a head. For a number of years, criminal defense lawyers have been mounting an attack on the breath testing device used in Georgia to detect the level of alcohol in the blood stream of suspected drunk drivers. Now, defenders are closer than ever to cracking the code.

At the heart of the controversy is the Intoxilyzer 5000, the device approved by the  state as the official breath testing device since 1995. The device is manufactured by CMI, Inc. a company out of Kentucky, and is used in several jurisdictions as well as government agencies and private firms. The device is designed to scan a sample of deep lung air with ultraviolet light and detect the amount of alcohol in the air. Internal software called the source code calculates the amount of alcohol in the bloodstream.

While the base models of the Intoxilyzer 5000 all work on the same principle, the model used in Georgia is unique in its features. CMI manufactures the device to meet specifications selected by the Georgia Bureau of Investigation Division of Forensic Sciences and selects some features while rejecting others.

The device is supposed to be equipped with certain failsafes to prevent false readings. These include detection for radio frequency interference, a means to rule out mouth alcohol as opposed to deep lung breath alcohol, and filters to rule out substances that could mimic alcohol in the test. Some of the options rejected by the state include a feature that allows the device to capture and seal a breath sample for independent testing as well as the ability to download results to keep a database of test results.

Defense lawyers have been skeptical of the Intoxilyzer 5000 since it was proposed by the GBI. On his website, noted Atlanta DUI lawyer William "Bubba" Head said that the device was originally manufactured in 1982, before the advent of cell phones and other devices that cause low level radio frequency and effect the accuracy of the test results. Defense lawyers have also noted other problems over the years to include issues with the volume of air required to provide a sufficient sample and the effects that some substances (smokeless tobacco, gum or mints) in the mouth have on (the test's) accuracy.

One of the biggest red flags to defense lawyers is the extent which CMI has gone to protect is proprietary device. All repairs and maintenance on the Intoxilyzer 5000 must be done by the manufacturer at its facility in Kentucky. Nobody in Georgia knows how the device works, not even the technicians who are charged to inspect, calibrate and certify each machine every quarter. Defense lawyers want to get ahold of the device to see if it works the way the manufacturer claims. However, CMI refuses to sell an Intoxilyzer to any third party.

At the heart of the controversy is the source code or the computer program that operates the Intoxilyzer. Thomas Workman, Jr, an engineer and computer programmer from Massachusetts with experience working for Xerox, Texas Instruments, Hewlett-Packard and IBM device emulation, contends that the source code for the Intoxilyzer 5000 consists of some 60,000 lines of code, making it highly probable there is a flaw somewhere in the programming. This has prompted defense lawyers to subpoena the computer program that runs the Intoxilyzer as well as the engineers that write the code. This is not so simple.

Because CMI and its employees are located in Kentucky, they are not subject to direct subpoenas from the Georgia courts. There is a two step process. First, the courts in Georgia must find that the out of state witness is material or necessary to the case. Second, the court in Kentucky must order the witness to appear in Georgia. CMI and prosecutors have fought these "source code motions" vigorously here in Georgia as well as in other states. In Georgia, the Prosecuting Attorneys Council, an agency that assists and coordinates the various prosecuting agencies throughout the state, has an attorney who is a resource to help prosecutors fight these motions.

Last year, defense lawyers received some help from the Supreme Court of Georgia on this issue. In June 2011, the Supreme Court issued opinions in Yeary v. State and Davenport v. State, which addressed the issue of materiality of the source code and gave the green light to forward the subpoenas on to the courts in Kentucky. Before long, defense lawyers will crack the DUI code and be able to put the Intoxilyzer 5000 to the test.  

To what end will the production of the source code bring? While prosecutors who stand by the reliability of the Intoxilyzer 5000 contend that it is a bit like the dog who catches the car, defense lawyers contend that the code will expose the flaws in the device. For many, this is an issue that goes beyond the prosecution of driving under the influence. It goes to transparency of government. If the government is going to use a computer program to arrest, convict and incarcerate its citizens, the government should disclose its methods and means.