A three-judge panel of the Sarasota County, Florida Circuit Court has given prosecutors fifteen days to produce the computer code underlying readings used to create drunk driving (DUI) convictions. The source code for the Intoxilyzer 5000 machine is responsible for tasks including the critical mathematical computations that produce the final reading of the subject's blood alcohol level.

More than 150 defendants banded together to challenge the Intoxilyzer, arguing that they faced serious criminal penalties and must have the opportunity to challenge fully the evidence used against them. Their lawyers produced evidence that the breath testing machines have been "upgraded" since Florida officials tested and approved them for use and that the only way to establish whether these modifications affect their accuracy is by checking the source code. The agency charged with assuring the accuracy of the device could not explain the changes made by the manufacturer.

Prosecutors counter that they can not produce the code because they do not have it. Only CMI, Inc., the device's manufacturer can produce the code. The state's contract with CMI stipulates that the source code must remain secret. The judges were not persuaded.

"An instrument or machine that if believed, establishes the guilt of an accused subjecting them to fines, loss of driving privileges and loss of freedom should be made available to the defense for open inspection," the court wrote in its order yesterday. "To construe the statute otherwise, is tantamount to granting the state authority to use confidential information (i.e. the software code) to establish the guilt of a criminal defendant without disclosing the information to the defendant for inspection and possible impeachment."

The judges cited a Florida Supreme Court ruling that mandating full access to the manuals and schematics of a breath testing machine and said this also applied to the code upon which the device operates. The judges stipulated that only one defense expert could see the code and that it could not be copied or disclosed in order to protect CMI's trade secrets.

The full text of the court order is available in a 423k PDF file at the source link below.