J Forensic Sci, March 2015, Vol. 60, No. 2 doi: 10.1111/1556-4029.12659 Available online at: onlinelibrary.wiley.com

TECHNICAL NOTE TOXICOLOGY AND CTA-SOCIETY

Nayak L. Polissar,1 Ph.D.; Wassana Suwanvijit,2 Ph.D.; and Rod G. Gullberg,3 M.S., PStat

The Accuracy of Handheld Pre-Arrest Breath Test Instruments as a Predictor of the Evidential Breath Alcohol Test Results

ABSTRACT: Drunk driving is a serious threat to public safety. All available and appropriate tools for curbing this threat should be employed to their full extent. The handheld pre-arrest breath test instrument (PBT) is one tool for identifying the alcohol-impaired driver and enforcing drunk driving legislation. A set of data was evaluated (n = 1779) where the PBT instrument was employed in drunk driving arrests to develop a multivariate predictive model. When maintained and operated by trained personnel, the PBT provides a reasonable estimate of the evidential test result within the relevant forensic range (95% prediction interval:  0.003 g/210 L). ROC analysis shows that a multivariate model for PBT prediction of the evidentiary alcohol concentration above versus below the legal limit of 0.08 g/210 L has excellent performance with an AUC of 0.96. These results would be of value in evidential hearings seeking to admit the PBT results in drunk driving trials.

KEYWORDS: forensic science, pre-arrest breath test, breath alcohol, multivariate model Driving while under the influence of alcohol (DUI) is one of the USA’s most serious public health issues. Many traffic safety organizations, including law enforcement, continue to investigate a variety of techniques and methods for reducing the adverse risk to public safety. Law enforcement, for example, continues to employ breath alcohol analysis as an investigatory and evidential tool for identifying the alcohol-impaired driver. Many law enforcement agencies now employ handheld pre-arrest breath test instruments (PBT) at the roadside to assist in determining if there is probable cause for arrest. These handheld instruments, indeed, add an element of objective assessment for identifying the driver who may have a breath alcohol concentration (BrAC) in excess of 0.08 g/210 L—the per se legal limit for drivers in all states of the United States. The use of the PBT instrument by the arresting officer is, in most jurisdictions, discretionary. The DUI offender is not required to submit to the PBT test under the current implied consent legislation in most states. In Washington state, for example, only ca. 50% of the DUI arrests have employed the PBT instrument prior to arrest. Implied consent legislation requires that an individual submit to an approved evidentiary breath alcohol test if an officer has reason to believe they are under the influence of alcohol, there is a lawful arrest and they are informed of their implied consent rights. Failure to submit to the evidentiary breath alcohol test results in driver’s license revocation in all

1

The Mountain-Whisper-Light Statistics, 1827 23rd Avenue East, Seattle, WA 98112. 2 Thaksin University, 140 Kanjanawanit Road, Muang Songkhla 90000, Thailand. 3 Clearview Statistical Consulting, 20119 61st Avenue SE, Snohomish, WA 98296. Received 19 July 2013; and in revised form 20 Dec. 2013; accepted 13 Mar. 2014.

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states. The PBT would provide, however, an additional important element in establishing probable cause for the arrest. Moreover, if the PBT result was determined to meet the criteria under US versus Frye (1) or Daubert v. Merrell Dow Pharmaceuticals (2), it would provide additional objective and admissible evidence for both probable cause and evidence of guilt. Arrests cannot be arbitrary. The officer must have objective and articulable evidence for a lawful arrest. In US versus Frye, the US Federal Circuit Court of Appeals required that new and novel scientific evidence be generally accepted within the relevant scientific community prior to being admissible as evidence in a criminal trial. Daubert was a more recent application of the Frye decision. The purpose here is to evaluate the evidentiary value of the PBT instrument and assess its predictive value in identifying drivers who will exceed the 0.08 g/210 L per se limit on a subsequent evidential test. The methodology is also applicable to limits other than 0.08 g/210 L. Indeed, data supporting the PBT instrument’s strong predictive value would provide support in evidential Frye or Daubert hearings attempting to obtain admissibility of their results in DUI litigation. While the primary purpose here is not to suggest that the PBT results will be evidential without further quality control considerations, findings such as those presented here may allow the PBT results to be admissible in court in support of the drunk driving offense under certain circumstances. Where the evidential test is not available, the PBT results provide evidence that should be considered by the court. A strong case can be made for the admissibility of the PBT results employing such methods and findings as presented here along with other considerations. Indeed, all evidence meeting the US versus Frye criteria should be admissible and allowed to be weighed by the jury. Previous research, as a result, has validated the analytical capability of PBT in different contexts (3–7). While previous research has presented the reliability of the Datamaster measurements, the present work expands on that by © 2014 American Academy of Forensic Sciences

POLISSAR ET AL.

employing a large sample of actual DUI arrest subjects and by developing a multivariate statistical model quantifying the extent to which the PBT is predictive of the subsequent evidential test result (8). Methods Official arrest data were obtained from the State of Washington as collected by a team of DUI enforcement officers within the Washington State Patrol. These officers are assigned fulltime to the enforcement of DUI laws within a specific region of the state of Washington. Each officer is equipped with a handheld PBT instrument and has been trained on its appropriate use. This group of officers was selected because of their focus and skill in the arrest of alcohol-impaired drivers and their use of breath test instruments. Two different PBT instruments were employed: the Alco-Sensor III and the Alco-Sensor FST (Intoximeters, Inc., St. Louis, MO). Both of these instruments quantify alcohol in the breath sample by means of chemical oxidation on a fuel cell surface. The more recent model, Alco-Sensor FST (n = 929), has breath sample acceptance criteria as well as an automatic blank test routine as part of its analytical protocol. The breath sampling criteria require the individual to provide a minimum volume and flow rate of breath before the sample is accepted for analysis. While lacking these features, the earlier Alco-Sensor III (n = 850) also requires the operator to manually depress a READ button for at least 30 s to allow the fuel-cell oxidation to be complete. Therefore, the results of the Alco-Sensor III are much more operator dependent than test results from the AlcoSensor FST. The total data set included 2877 DUI arrests (both with and without PBT results) and encompassed dates from January 3, 2008 to August 31, 2011. From this total data set, 1784 (62%) of the records included cases which subsequently had the legally mandated two breath samples in the BAC Datamaster instrument (the evidential test instrument; National Patent Analytical Systems, Inc., Mansfield, OH) as well as one PBT result along with its collection time recorded. From this dataset, n = 5 outlier values, all at low (

The accuracy of handheld pre-arrest breath test instruments as a predictor of the evidential breath alcohol test results.

Drunk driving is a serious threat to public safety. All available and appropriate tools for curbing this threat should be employed to their full exten...
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