Sometimes we take for granted that forensic science is reliable when it isn’t. And because we legitimately fear drunk driving, the volume of cases can lead judges to be a bit cynical about challenges to the local police methodology. Just because there is a challenge does not necessarily make it true. The device that has been approved  in New Jersey illustrates the challenges courts face.

Mark Denbeaux, Nathan W. Kahl, Nicholas Snow, Richard Eschle, Marissa Litwin, Keith Oliver and Robert DiPisa (Seton Hall University, School of Law, Seton Hall University, Seton Hall University, Seton Hall Law School – Center for Policy & Research, Seton Hall University – Center for Policy & Research, Seton Hall University – Center for Policy & Research and Seton Hall University – Center for Policy & Research) have posted The Untestable Drunk Driving Test on SSRN. Here is the abstract:

The intersection of law and science has a long and tortuous history, but a new chapter is being written in New Jersey with the state’s use of the Alcotest 7110 MK III-C for prosecuting drunk driving traffic offenses. As the name implies, this is a device which purports to test levels of intoxication by measuring breath alcohol levels in order to determine blood alcohol concentration. The Alcotest is a proprietary device purchased by the State of New Jersey for use by law enforcement under a contract with the manufacturer that prohibits the State from subjecting the device to “reverse engineering” testing. Although the Alcotest was approved for use by the New Jersey Supreme Court after a proceeding that explored its reliability, serious scientific and legal questions remain, largely because of the manufacturer’s refusal to sell a device for independent testing or permit the State to provide its devices for such assessment. Given this limitation, any conclusions about the Alcotest are necessarily tentative. Nevertheless, as detailed in this Report, there are serious reasons to doubt the accuracy and reliability of the test, especially the manufacturer’s claims of the superiority of its product because, unlike other devices, the Alcotest employs two independent measures of breath alcohol. In reality, the two measures are highly interdependent. In addition, there are other reasons to question the validity of the test as an accurate measure of intoxication.
The Alcotest machine and the process by which it has been adopted raise the following novel issues:

• In New Jersey, the Alcotest device has been adopted to the exclusion of all other devices. The Alcotest is now the only breath alcohol analyzer of record in the state.

• The Alcotest device is now ‘immunized’ from challenge and from outside testing, and doubly so:

• By New Jersey’s contract with Draeger, which allows Draeger to prohibit any entity other than the state from purchasing the Alcotest, and

• By the decision in State v. Chun, which acknowledges Draeger’s intellectual property rights to the source code of the Alcotest, thus preventing any outside entity from determining how the machine works.

• Measurement devices like the Alcotest are inherently inexact, not because of oversights or poor design but because any measurement carries with it measurement errors. Sources of error for previous machines were reasonably well investigated, documented, and understood. The Alcotest, while new and theoretically better than previous designs, is also subject to measurement error, but because of the Alcotest’s immunity to challenge, those sources of error are currently not subject to investigation by scientists, let alone litigants.

The point — that a consequential and relatively ubiquitous scientific instrument is unavailable for scientific purposes, under any circumstances — is more than a theoretical issue.

The hallmark of the scientific process is testing and peer review. As matters now stand, it is impossible to test and review the Alcotest in the courts, and Dr. Snow’s experiences show that it is further exempted from testing and review in the scientific community.

This report investigates the process by which the Alcotest was adopted; the extent to which it is immune from testing; the reason that such immunization is dangerous in light of the science of breathalyzers in general and the Alcotest in particular; and, finally, the legal consequences of admission of evidence that cannot be tested either in general or in this particular case. Because science lies at the core of the legal issues surrounding the use of the Alcotest, Part Two of this report describes the science behind blood alcohol tests in general and the Alcotest in particular. Part Three considers the circumstances and the Special Master’s decision of State v. Chun. Finally, the report’s conclusion addresses the legal consequences of the aforementioned testing prohibitions upon the use of the device in litigation