Opinion ID: 1989907
Heading Depth: 2
Heading Rank: 3

Heading: How the Alcotest Works

Text: The State seeks in this proceeding to establish that the Alcotest is scientifically reliable to measure defendants' blood alcohol levels. We turn, then, to a discussion of the physiological effects of alcohol on the body, how the Alcotest measures the concentration of alcohol in the breath and converts it to a measure of blood alcohol levels, and the State's proposed procedures to ensure that the Alcotest functions properly.
Much of the scientific evidence in the record before the Court is undisputed. In fact, the basic physiological mechanisms on which all breath testing devices rely are not themselves controversial. We set these scientific propositions forth here, however, to provide the basis for our analysis of the scientific matters that are in dispute.
Alcohol is ordinarily ingested orally and enters the stomach where it is absorbed through the stomach's walls and intestines and is thereafter carried by the blood through the liver to the heart. The heart pumps the blood and, along with it, the alcohol, through the body, including carrying it to the brain and the lungs. Alcohol exerts its effects on an individual when the blood containing the alcohol reaches the brain. Absorption begins immediately once a person starts drinking. The rate of absorption varies greatly from one person to the next and can even vary in the same person at different times. It depends on a wide variety of factors including general health, recent food consumption, physical makeup, amount of alcohol consumed, weight, and gender. Elimination of alcohol also starts as soon as a person begins to drink. Alcohol is eliminated through excretion and metabolization, which occur when alcohol passes through the liver and is broken down by enzymes and dehydrogenates. When a person's body is absorbing alcohol faster than he or she is eliminating it, the concentration of alcohol in the blood will continue to rise. This period of time is ordinarily referred to as the absorptive phase. The concentration will reach its peak, and it will achieve a plateau, at the time when elimination and absorption are occurring at about the same rate. When the person stops ingesting alcohol, or slows down ingestion to the point where the body is eliminating alcohol more quickly than absorbing it, the body enters what has generally been referred to as the post-absorptive phase. During this period of time, the concentration of alcohol in the blood decreases.
The reported concentration of alcohol in any particular person varies depending upon the source of the test sample. An understanding of the relationship of these potential test sample sources to BAC is important to our analysis. Alcohol passes into the lungs, through the walls of the air sacs, called alveoli. As it does so, it mixes with the air that the person has inhaled. When the person exhales, alcohol passes out of the body as part of the breath. An individual's breathing pattern can influence the amount of alcohol that appears in any particular breath. In addition, the amount of alcohol in the breath sample represented by a single act of exhalation will vary from the beginning to the end. This is because the breath actually comes from different parts of the body, from the mouth to the deepest part of the lungs. Except for the possible interference that would occur if the test subject had ingested alcohol so recently that residual mouth alcohol were captured, the first part of the breath comes from the mouth and throat where there is little contact with the alcohol passing through the alveoli. However, as the person continues to exhale, the expelled air comes from deeper in the respiratory system, where it contains alcohol that more closely represents the amount passing through the lungs from the circulating blood.
Our statute establishes the violation in terms of blood, and not breath alcohol concentration. Although testing an individual's blood would presumably provide more direct evidence of that person's BAC, there are obvious practical and logistical problems associated with attempting to collect blood samples from suspected drunk drivers routinely. As a result, although because of our statute New Jersey is considered to be a blood state, we have long permitted BAC to be established through breath testing, in which breath samples are tested and converted to determine blood alcohol levels. Breath testing therefore uses an indirect measure of BAC by calculating the alcohol concentration in the breath (breath alcohol concentration, or BrAC) and extrapolating to derive the BAC using a blood/breath ratio. Breath testing has become the preferred method for field testing because it can be performed easily, is highly automated, does not require scientific skill, and produces an immediate result.
In light of the fact that breath testing always relies on the extrapolation of BAC through testing of breath, the precision with which any device evaluates BAC through this method is critical to our consideration of the admissibility of the device's results. We turn then to a description of the manner in which the Alcotest operates. The Alcotest, which is currently in use in seventeen of our twenty-one counties, [9] as well as in other states, including Alabama and parts of New York, is a device that purports to accurately measure the concentration of alcohol from a human subject through breath testing. The Alcotest is an embedded system, meaning that it is a device with a specific purpose, and it relies on pre-loaded software that the manufacturer refers to as firmware. The Alcotest uses both infrared (IR) technology and electric chemical (EC) oxidation in a fuel cell to measure breath alcohol concentration. The device therefore produces two test results for each breath sample, one derived from an IR reading and the other, by and large, from an EC reading. Although the precise mechanism by which these tests are accomplished is not relevant to the issues before us, the IR chamber, also called a cuvette, captures the breath sample and uses infrared energy to calculate absorption of the energy by the alcohol concentrated in the chamber. IR technology has been available since the 1970's or early 1980's and scientists have concluded that it is reliable. See, e.g., Foley, supra, 370 N.J.Super. at 350, 851 A. 2d 123. The EC, or fuel cell technology, uses a catalyst to absorb alcohol and provide a second measurement [10] of breath alcohol concentration from a small sample captured from the cuvette. In the EC chamber, voltage is applied to cause the catalytic reaction, which causes any alcohol that is present to oxidize. As that occurs, the oxidation process creates electricity, which is then measured to determine the amount of alcohol interacting with the fuel cell.
The Alcotest reports the IR and EC readings on a printout from the machine, referred to as the Alcohol Influence Report (AIR). [11] One of the claimed advantages of the Alcotest, as compared to the breathalyzer, is that it is not operator-dependent, but performs its analysis in accordance with a sequence through a computerized program that gives visual prompts to the operator. We turn, then, to a description of the manner in which the device operates in practice in performing these functions. The actual administration of the test is performed by one of the more than 5000 certified Alcotest operators in New Jersey. When a person has been arrested, based on probable cause that the person has been driving while intoxicated, he or she is transported to the police station to provide a sample for the Alcotest. The Alcotest, consisting of a keyboard, an external printer, and the testing device itself, is positioned on a table near where the test subject is seated. Operators must wait twenty minutes before collecting a sample to avoid overestimated readings due to residual effects of mouth alcohol. The software is programmed to prohibit operation of the device before the passage of twenty minutes from the time entered as the time of the arrest. Moreover, the operator must observe the test subject for the required twenty-minute period of time to ensure that no alcohol has entered the person's mouth while he or she is awaiting the start of the testing sequence. In addition, if the arrestee swallows anything or regurgitates, or if the operator notices chewing gum or tobacco in the person's mouth, the operator is required to begin counting the twenty-minute period anew. The Alcotest that is the focus of this matter utilizes software developed in collaboration with the New Jersey State Police and known as New Jersey Firmware version 3.11. [12] This software prompts the operator through a specific testing sequence on each arrestee. Essentially, the process begins when the operator has typed identifying information into the machine through a series of questions and prompts. The device then starts and automatically samples the room air to determine if there are chemical interferents in the room. This is known as a blank air test. Assuming that there are none, the machine then uses its attached wet bath simulator to heat a solution and produce a vapor sample from a control test solution [13] with a known alcohol concentration of 0.10, which is then measured using IR and EC technology. In order to be valid, the control test, in accordance with currently-programmed firmware, must produce results between 0.095 and 0.105. If the results do not identify the known sample within the defined parameters, the device is programmed so that the test cannot proceed. If the machine is working properly as demonstrated by the control test, then the instrument performs a second blank air test, again using room air to purge the test sample out of the chamber. Assuming that the results of the control test are within the established parameters, the instrument prompts the operator through a message on the LED screen to collect a breath sample. The operator then attaches a new, disposable mouthpiece and removes cell phones and portable electronic devices from the testing area. The operator is required to read the following instruction to the test subject: I want you to take a deep breath and blow into the mouthpiece with one long, continuous breath. Continue to blow until I tell you to stop. Do you understand these instructions? The arrestee then provides the first breath sample, which is measured in the IR and EC chambers. Lights on the LED screen and an audible sound alert the operator when a breath sample which meets the minimum fixed standards, comprised of four criteria, has been provided. The operator then tells the subject to stop and the instrument performs a third blank test to purge the first breath sample. After a two-minute lock-out period during which the device will not permit another test, the instrument prompts the operator to read the instruction again to the arrestee and collect the second breath sample. The second sample is also measured using the IR and EC technology. The second sample is purged from the machine and the device performs a fourth blank test using room air. If the measurements for the first breath test are out of the accepted range of tolerance with the measurements for the second breath test, the machine prompts the operator to conduct a third breath test. Depending on the relationship among the three tests, the results are reported. The instrument then performs a second control test with the known solution from the simulator. Finally, the air is purged again and a final blank test is performed. The device gives the operator three minutes to collect each sample. If that time expires without a sample, the device will present the operator with three options. The options are to terminate the test, report that the person refused the test, or continue with the test. If the officer opts to continue the test, the device will purge itself and then prompt the operator to collect another sample. The operator has a maximum of eleven attempts to collect two breath samples. After the eleventh failed test, the only two options permitted by the device are to terminate testing or report refusal. [14] As currently configured by New Jersey Firmware version 3.11, the software now being utilized, the device will accept a sample only if it meets certain minimum criteria that have been devised by the State. [15] Once the subject has provided an acceptable breath sample, the machine prompts the operator, through a system of lights on the LED screen and an audible beep, to tell the subject that he or she may stop. If any of these minimum test criteria has not been met, the machine will generate an error message and a report of how much air was submitted. The machine then offers the operator the option of giving the person another attempt or asserting refusal. The results of the test sequence are printed out from the device in a sequentially numbered document referred to as an AIR. The AIR contains the test subject's identifying information, date, time, and test results for each stage of the procedure. Each AIR includes a variety of other information relevant to the test, including the serial number of the device used in the test, dates of and file numbers for calibration and linearity checks, and solution control lot and bottle numbers. The operator must retain a copy of the AIR and give a copy to the arrestee. In the event that the administration of the test resulted in errors because of, for example, insufficient breath volume or duration, the AIR will report those errors and will not attempt to calculate the BAC from an inadequate sample. Similarly, if the results of the control test do not fall within the acceptable tolerance, the device will produce an AIR that reports that the test could not be accomplished because of an invalid control test. If the results are within the acceptable tolerance, the AIR shows the BAC values for each IR and EC reading for each of the tests to three decimal places. The AIR then reports the final BAC test result, which will be the lowest of the four acceptable readings, that is, readings within acceptable tolerance, which the device is programmed to truncate to two decimal places. Truncating, as opposed to rounding, involves simply reporting the first and second decimal places and dropping the third. For example, by truncating, a reading of 0.079 percent BAC would be reported as 0.07 and a reading of 0.089 percent BAC would be reported as 0.08. The effect of truncating, as opposed to rounding, is to under-report the concentration, to the benefit of the arrestee. By statute, the Legislature has designated the Attorney General to create and implement a breath testing program. See N.J.S.A. 39:4-50.3. The Attorney General, in turn, has vested responsibility for carrying out this command in the State Police. See N.J.A.C. 13:51-3.2. The Alcotest program was designed and is overseen by the Office of Forensic Sciences, a Division of the New Jersey State Police. The director of the forensic laboratory, Dr. Thomas Brettell, together with other forensic scientists in the Office assigned to the alcohol/drug testing unit, conducted tests on a variety of breath testing devices in an effort to select a successor to the breathalyzer. After the Alcotest was chosen, Brettell assisted in the creation of the test criteria and provided other input into the original programming and the updates to the software that now is utilized in operating the device. His office has collaborated with municipalities to train Alcotest operators and to oversee certain aspects of the program. State Police Sergeant Kevin Flanagan is the field supervisor for five State Police coordinators, each of whom monitors a geographic area. The coordinators receive factory and classroom training from Draeger and they, in turn, train the operators. Coordinators do not perform any repairs, but they perform black key functions, such as calibration and software uploads, which are not done by other police personnel. Calibration of the machines involves attaching the machine to an external simulator which uses a variety of solutions of known alcohol concentrations to create vapors that approximate human breath. By exposing the IR and EC mechanisms to these differing concentrations, and by analyzing the device's ability to identify accurately each of those samples within the acceptable range of tolerance, referred to as a linearity test, the coordinator is able to ensure that the machine is correctly calibrated. When coordinators undertake to perform this calibration, currently on an annual basis, and other routine inspections, they also download the device's test information onto two compact discs. [16] In accordance with current State Police protocol, one of these discs is kept in the local police department's evidence file and the other is held by the coordinator. [17]