Opinion ID: 1989907
Heading Depth: 3
Heading Rank: 1

Heading: EC Readings and Fuel Cell Drift Algorithm

Text: One of the most controversial findings that came out of the second remand proceedings, during which the parties were afforded the opportunity to undertake an analysis of the source code that is the heart of the operation of the Alcotest device, related to the EC readings. During the proceedings, the Special Master summoned Brian Shaffer, a Draeger employee responsible for the code and for implementing changes to the New Jersey Firmware since the Foley decision, to testify. Near the end of his testimony, Shaffer revealed that Firmware version 3.11 utilizes a compensating algorithm to account, in part, for a phenomenon known as fuel cell drift. As Shaffer explained it, the EC reading is obtained by passing an electrical current through a small sample of the breath that has otherwise been captured for IR testing in the cuvette. The fuel cell that creates the electrical charge reacts in the presence of alcohol. The reaction of the fuel cell can be represented graphically as a curve and the percentage of alcohol in the breath is measured by calculating the area under the curve mathematically. As fuel cells age, the area under the curve that expresses the same breath alcohol content is unchanged, but the shape of the curve itself changes from a high sharp peak to a longer, flatter one. As a matter of mathematical computation, the area being measured is the same even though the curves, were they plotted graphically, would appear to be different when observed visually. According to Shaffer, the flattening of the curve is caused by the aging of the fuel cell, which reacts more slowly and with less intensity to the same amount of alcohol than when the fuel cell is new. This phenomenon, known as fuel cell drift, does not actually alter the accuracy of the EC measurement. However, because the fuel cell begins to react more slowly to the presence of alcohol as it ages, a portion of the area under the curve that is the basis for the alcohol measurement is not captured during the time when the Alcotest EC data is collected. Instead, a portion of the end of the curve is, in essence, cut off, resulting in a lower than accurate measurement. Because fuel cell drift is a known scientific phenomenon that would otherwise result in an inaccurate underreporting of the percentage of alcohol in the test subject's breath, Draeger added a compensating algorithm into the firmware. The EC fuel cell drift algorithm, therefore, is intended to capture a portion of the missing data and, in theory, create a more accurate result as the reported EC reading. The algorithm, however, does not attempt to quantify the missing area under the curve per se, but instead attempts to compensate in part for the lack of complete data arising from the EC measurement. In the event that fuel cell drift is detected during the control test, the algorithm mathematically increases the EC reading that is reported by up to twenty-five percent of the difference between the IR and EC readings from the tests of the subsequent breath samples. The compensating algorithm is not routinely applied, but only functions if the appropriate preconditions are met. The device, in performing the control test, compares the EC and the IR readings and accurately reports those results. Because the control test utilizes a known test solution to ensure that the device is functioning properly and that it accurately reads a solution of a known percentage of alcohol, fuel cell drift can be detected from the control test's results. If the device detects drift, the algorithm will adjust the EC measurement standard, which, in turn, will slightly increase the reported EC results for the test subject's breath sample to account for the fuel cell drift. The discovery of the EC fuel cell drift algorithm in the source code prompted the Special Master to conclude that more frequent re-calibration of the devices with replacement of fuel cells that had become depleted would reduce reliance on the EC fuel cell drift algorithm and, therefore, increase the accuracy of the readings. The State objects to this proposal as unnecessary and burdensome, arguing that its current program of annual calibration is sufficient. Defendants, on the other hand, raise several challenges to this EC algorithm, both in theory and in practice. First, they argue that it demonstrates that Draeger's claim that the device uses two completely independent measurements for breath alcohol is false. Second, they argue that it demonstrates that the device is simply not accurate in any sense. Third, they argue that the algorithm, which they attack as having been hidden from them throughout the initial remand proceedings, is evidence that the software may be utilizing other hidden mechanisms that might inflate readings so that the accuracy of the results can never be reliable. We do not share either the State's or defendants' concerns. The record reflects that a semi-annual inspection and recalibration program recommended by the Special Master is consistent with the manufacturer's recommendations. At the same time, it provides a useful safeguard by affording a more regular opportunity to evaluate and replace aging fuel cells. We discern no reason to permit the State to continue to adhere to its program of annual recalibration, particularly in light of the concerns raised as to the utilization of a compensating algorithm in the interim. However, we do not find merit in defendants' concerns about the EC algorithm or its use. There is sound scientific evidence that supports the conclusion that fuel cells begin to age as soon as they are put into service and that fuel cell drift is inevitable. But there is equally ample support for the proposition that even as the intensity of the peak demonstrated by the EC evaluation of the sample diminishes over time, the reactive effect overall (that is, the area under the curve being calculated) does not. Instead, the time within which the test is performed simply truncates the EC reading before all of the otherwise appropriate data can be generated. Theoretically, one could, perhaps, program the machine to calculate the missing area based on a presumed regularly-shaped curve. Although that might even be a more accurate method of supplying the missing data, it would not, in the end, be as advantageous to defendants as is the minor upward adjustment that the algorithm effects. Indeed, because the device will not generate a result that can be utilized if the readings are out of tolerance, the algorithm alters the EC result in an amount that, we are confident, cannot fairly be seen as convicting the innocent. Nor do we consider the fact that the algorithm was unknown until Shaffer revealed it or the fact that neither of the independent experts who evaluated the source code recognized its existence to be indicative of any broader shortcoming in the firmware. Two reasons support this result. First, in black box testing, the machine performed accurately by demonstrating the ability to identify the percentage of alcohol in known solutions within the applicable tolerance parameters. Were there a fundamental defect in the source code, one would expect that the machine would not be able to perform in this fashion. Second, the evidence in the record demonstrates that the EC reading is not always less than the IR reading either during control tests or in actual testing. If, as defendants fear, the EC is always being artificially inflated to approximate, if not absolutely match, the IR, one would expect to find only results in which the IR was the higher reading. That, however, is simply not the case, as there are numerous examples of readings from both actual and control tests in which the EC reading is higher than the IR. We cannot therefore conclude that the source code includes hidden commands to artificially inflate the EC to raise it to the level of the IR. Finally, however, defendants argue that the existence of the EC algorithm calls into question all of the testimony received during the original remand proceedings. They point out that several witnesses referred to the fact that the Alcotest uses two independent testing methods as proof of its superiority and as support for their opinions that the device is scientifically reliable and accurate. They further point to Draeger's representations to the State that this technology made the device superior to others which was essentially accepted by the Special Master. Although the use of this algorithm certainly undercuts the accuracy of the marketing claims made by Draeger, it does not, in and of itself, alter the support in the record for the conclusion by the Special Master about the general scientific reliability of the device.