In driving under the influence (DUI) cases, prosecutors habitually rely on the results from breathalyzer tests as proof of the defendant’s blood alcohol level at the time of arrest. In response, DUI defendants often attempt to compel discovery of the source code contained in the test device, which can reveal whether the breath test at issue was performed accurately. Despite the popularity of this strategy, nearly all states to consider the issue have denied the defendant’s motion for discovery of breathalyzer source code. The majority of courts construe state and federal rules of criminal procedure to limit discovery orders to information within the “possession, custody or control” of the prosecution and summarily hold that breathalyzer source code is not in the State’s possession or control. Absent a contractual agreement granting the State proprietary rights to the code, the courts have failed to articulate a clear definition of what it means to be in possession, custody, or control of breathalyzer source code. This Article explores the classification of breathalyzer source code, the discovery rules surrounding its disclosure, and the implications of its protected legal status
