Previous works investigated a spectroscopic technique that offered a promising alternative to blood and breath assays for determining in vivo alcohol concentration. Although these prior works measured the dorsal forearm, we report the results of a 26-subject clinical study designed to evaluate the spectroscopic technique at a finger measurement site through comparison to contemporaneous forearm spectroscopic, venous blood, and breath measurements. Through both Monte Carlo simulation and experimental data, it is shown that tissue optical probe design has a substantial impact on the effective path-length of photons through the skin and the signal-to-noise ratio of the spectroscopic measurements. Comparison of the breath, blood, and tissue assays demonstrated significant differences in alcohol concentration that are attributable to both assay accuracy and alcohol pharmacokinetics. Similar to past works, a first order kinetic model is used to estimate the fraction of concentration variance explained by alcohol pharmacokinetics (72.6-86.7%). A significant outcome of this work was significantly improved pharmacokinetic agreement with breath (arterial) alcohol of the finger measurement (mean k(Art-Fin) = 0.111 min(-1)) relative to the forearm measurement (mean k(Art-For) = 0.019 min(-1)) that is likely due to the increased blood perfusion of the finger.

Learn More >

The Driver Alcohol Detection System for Safety Program is a research partnership between the National Highway Traffic Safety Administration and the Automotive Coalition for Traffic Safety. The cooperative agreement seeks to assess the current state of detection technologies that are capable of measuring blood alcohol concentration, and to support the development and testing of prototypes and subsequent hardware that could be installed in vehicles. Three Phase I proof-of-principle prototype sensors now have been developed. Two of the sensors are designed to remotely measure alcohol concentration in drivers’ breath from the ambient air in the vehicle cabin, and the third is designed to measure alcohol in the drivers’ finger tissue through placement of a finger on the sensor. To validate the performance of the prototypes, unique standard calibration devices have been developed for both the breath- and touch-based systems that exceed current alcohol-testing specifications. A testing program was undertaken to provide an understanding of whether the devices ultimately can meet the performance specifications needed for non-invasive alcohol testing. Bench testing determined the prototypes’ accuracy, precision, and speed of measurement and established what additional development will be needed in Phase II. Limited human subject testing permitted an understanding of the in vivo relationship among the various measures of blood alcohol as provided by blood, breath, and the prototype devices. This paper provides the results of prototype testing and outlines further development needed.

Learn More >

Alcolocks and alcohol screening devices are becoming commonplace, and their use is expected to grow rapidly with cost reduction and improved usability. A new breath analyzer prototype is demonstrated, with the prospects of eliminating the mouthpiece, reducing expiration time and volume, improving long-term stability, and reducing life cycle cost. Simultaneous CO2 measurements compensate for the sample dilution and unsaturated expiration. Infrared transmission spectroscopy is used for both the alcohol and CO2 measurement, yet the entire system is contained within a small handheld unit. Experimental results are reported on the device sensitivity, linearity, resolution, and influence from varying measuring distance. The correlation between early and full-time sampling was established in 60 subjects. Basic concept verification was obtained, whereas resolution and selectivity still needs to be improved. Further improvements are expected by system optimization and integration.

Learn More >

State-of-the-art breath analysers require a prolonged expiration into a mouthpiece to obtain the accuracy required for evidential testing and screening of the alcohol concentration. This requirement is unsuitable for breath analysers used as alcolock owing to their frequent use and the fact that the majority of users are sober drivers; as well as for breath testing in uncooperative persons.

This thesis presents a method by which breath alcohol analysis can be improved, using carbon dioxide (CO2) as the tracer gas, offering quality control of the breath sample, enabling the mouthpiece to be eliminated, and bringing about a significant reduction in the time and effort required for a breath alcohol screening test. With simultaneous measurement of the ethanol and the CO2 concentrations in the expired breath, the end-expiratory breath alcohol concentration (BrAC) can be estimated from an early measurement, without risk of underestimation.

Comparison of CO2 and water as possible tracer gases has shown that the larger intra- and interindividual variations in the (end-expiratory) concentration is a drawback for CO2 whereas the advantages are a low risk of underestimation of the BrAC, and the limited influence from ambient conditions on the measured CO2 concentration. The latter is considered to be of importance because the applications likely imply that the breath tests will be conducted in an uncontrolled environment, e.g., in a vehicle or ambulance. In emergency care, the measurement of the expired CO2 concentration also provides the physicians with information about the patient’s respiratory function.

My hope and belief, is that with a more simple, reliable and, user-friendly test procedure, enabled with the simultaneous measurement of the CO2 in the breath sample, the screening for breath alcohol will increase. An increased number of breath alcohol analysers installed as alcolocks and more breath alcohol tests conducted in emergency care, is likely to save lives and diminish the number and severity of injuries.

Learn More >

The Automotive Coalition for Traffic Safety (ACTS) and the National Highway Traffic Safety Administration (NHTSA) have commenced a five-year cooperative agreement exploring the feasibility of, and the public policy challenges associated with, widespread use of in-vehicle alcohol detection technology to prevent alcohol-impaired driving. This effort, known as the Driver Alcohol Detection System for Safety (DADSS) program, aims to develop technologies that could be a component of a system to prevent the vehicle from being driven when the device registers that the driver’s blood alcohol concentration (BAC) exceeds the legal limit (currently 0.08 g/dL throughout the United States). For DADSS installation as original equipment in new vehicles there are critical requirements to be met. Alcohol detection technology must be seamless to the driver and be able to quickly and accurately measure the driver’s BAC non-invasively. DADSS devices must be compatible for mass-production at a moderate price, be durable, meet high levels of reliability, and require little or no maintenance. Potential technological approaches have been identified and thorough analyses undertaken to determine candidates for further development, utilizing a clear understanding of the processes by which alcohol is absorbed into the blood stream, distributed within the body, and eliminated from it. This paper describes what is known regarding alcohol measurement via various methods, and details which technologies deserve further study. Two approaches are identified that have considerable promise in measuring driver BAC non-invasively within the time and accuracy constraints: 1) Tissue Spectrometry, a touch-based approach allowing estimation of alcohol in tissue through detection of light absorption at a particular wavelength from a beam of near-infrared light reflected from within the subject’s tissue, 2) Distant Spectrometry using part of the infrared light spectrum where the light is transmitted toward the subject from a source that receives and analyses the reflected and absorbed spectrum, thereby allowing assessment of alcohol concentration in the subject’s exhaled breath.

Learn More >

While government regulations play an important role in ensuring vehicle safety, voluntary approaches to the design and implementation of vehicle safety systems are increasing in importance as vehicle manufacturers deploy safety systems well in advance of, and even in the absence of, government regulations requiring them. This paper provides an overview of regulatory and non-regulatory approaches to vehicle technology development and deployment, and will describe a new, innovative public\private partnership underway to develop an in-vehicle alcohol detection system. In response to concerns about limited progress in reducing alcohol-impaired driving in the United States during the last decade, attention is focusing on technological approaches to the problem. One strategy includes efforts to increase the application of current breath alcohol ignition interlocks on the vehicles of Driving While Intoxicated (DWI) offenders. However, in recognition that many alcohol-impaired drivers have not been convicted of DWI, an effort is underway to develop advanced invehicle technologies that could be fitted in vehicles of all drivers to measure driver blood alcohol concentration non-invasively. The Automotive Coalition for Traffic Safety (ACTS, a group funded by vehicle manufacturers) and the National Highway Traffic Safety Administration (NHTSA) have commenced a 5- year cooperative agreement entitled Driver Alcohol Detection System for Safety (DADSS) to explore the feasibility of, and the public policy challenges associated with, widespread use of invehicle alcohol detection technology to prevent alcohol-impaired driving. This paper will outline the approach being taken, and the significant challenges to overcome.