Objective: The research objective of the present investigation is to demonstrate the present status of passive in-vehicle driver breath alcohol detection and highlight the necessary conditions for large-scale implementation of such a system. Completely passive detection has remained a challenge mainly because of the requirements on signal resolution combined with the constraints of vehicle integration. The work is part of the Driver Alcohol Detection System for Safety (DADSS) program aiming at massive deployment of alcohol sensing systems that could potentially save thousands of American lives annually.

Method: The work reported here builds on earlier investigations, in which it has been shown that detection of alcohol vapor in the proximity of a human subject may be traced to that subject by means of simultaneous recording of carbon dioxide (CO2) at the same location. Sensors based on infrared spectroscopy were developed to detect and quantify low concentrations of alcohol and CO2. In the present investigation, alcohol and CO2 were recorded at various locations in a vehicle cabin while human subjects were performing normal in-step procedures and driving preparations. A video camera directed to the driver position was recording images of the driver’s upper body parts, including the face, and the images were analyzed with respect to features of significance to the breathing behavior and breath detection, such as mouth opening and head direction.

Results: Improvement of the sensor system with respect to signal resolution including algorithm and software development, and fusion of the sensor and camera signals was successfully implemented and tested before starting the human study. In addition, experimental tests and simulations were performed with the purpose of connecting human subject data with repeatable experimental conditions. The results include occurrence statistics of detected breaths by signal peaks of CO2 and alcohol. From the statistical data, the accuracy of breath alcohol estimation and timing related to initial driver routines (door opening, taking a seat, door closure, buckling up, etc.) can be estimated.

The investigation confirmed the feasibility of passive driver breath alcohol detection using our present system. Trade-offs between timing and sensor signal resolution requirements will become critical. Further improvement of sensor resolution and system ruggedness is required before the results can be industrialized.

Conclusions: It is concluded that a further important step toward completely passive detection of driver breath alcohol has been taken. If required, the sniffer function with alcohol detection capability can be combined with a subsequent highly accurate breath test to confirm the driver’s legal status using the same sensor device. The study is relevant to crash avoidance, in particular driver monitoring systems and driver–vehicle interface design.

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Alcohol-related traffic crashes and deaths remain a major problem in the United States as 2014 data revealed that there were 32,675 traffic fatalities that year, with 31% of them being related to alcohol. The National Highway Traffic Safety Administration (NHTSA) and the Automotive Coalition for Traffic Safety (ACTS) began research in February 2008 aimed at identifying potential in-vehicle approaches to the problem of alcohol-impaired driving that are sensitive, reliable and less intrusive than ignition interlocks. The Driver Alcohol Detection System for Safety (DADSS) was created, and two passive technologies based on breath- and touch (tissue)- based systems for detecting alcohol were selected to be tested against a research grade hand-held breathalyzer device and venous blood.

Healthy male and female volunteers (age 21-40) signed an Institutional Review Board (IRB)-approved informed consent and participated in experiments in which they consumed 0.9 g/kg of alcohol (vodka) under a variety of drinking regimens and scenarios that mimicked real-life situations. The volunteers then provided passive breath and tissue (i.e., finger touch) samples and had their blood drawn for subsequent quantification of alcohol via gas chromatography. The lag time of appearance of alcohol in each sample as well as peak concentration, time to peak, and elimination rate were the primary dependent variables. The overall aim of the experiments was to test whether the alcohol levels measured by the two prototype devices correlate with venous blood under the following scenarios: lag time, eating a snack, eating a full meal, exercising, and “last call”.

The lag time experiment revealed that the order of alcohol appearance after drinking was (from quickest to slowest): breath, blood, and tissue, although the early breath samples were contaminated by mouth alcohol. However, the concentration-time curves for both prototype devices paralleled that of blood. Similar profiles were observed in the “last call” experiment with a “surge” of alcohol being observed after an extra drink was consumed during the distribution phase. The exercise scenario revealed similar profiles, although the touch-based device registered a slightly higher alcohol level. Finally, the two eating scenarios indicated that blood alcohol concentrations were lower after consuming a meal compared to a snack, and breath and touch samples reflected these patterns.

The sample size of 10 individual participants is small, but individuals served as their own controls by participating in more than one experiment. Furthermore, the study is ongoing and so the sampling limitation will be addressed. The data support the proof-of-concept that passive technologies can detect alcohol quickly and are not affected by many of the common scenarios that alter blood alcohol concentrations. Such devices, if proven to be reliable and reproducible with additional human testing, represent a significant technological breakthrough in strategies to reduce alcohol-impaired individuals from driving a vehicle and causing injuries and/or deaths.

The National Highway Traffic Safety Administration (NHTSA) and the Automotive Coalition for Traffic Safety (ACTS) began research in February 2008 to try to find potential in-vehicle approaches to the problem of alcohol-impaired driving. Members of ACTS comprise motor vehicle manufacturers representing approximately 99 percent of light vehicle sales in the U.S. This cooperative research partnership, known as the Driver Alcohol Detection System for Safety (DADSS) Program, seeks to develop technologies that are less intrusive than the current in-vehicle breath alcohol measurement devices. Detection technology must be seamless (passive) with the driving task. It also must be able to quickly and accurately measure a driver’s blood alcohol concentration (BAC) in a non-invasive manner. These technologies will be a component of a system that may deter the vehicle from being driven when the device registers that the driver’s BAC exceeds the legal limit. Such devices ultimately must be compatible with mass-production at a moderate price, be durable, meet high levels of reliability, and require no maintenance. Therefore, the performance standards for the adoption of these devices among the general public, many of whom do not drink, let alone drink and drive, must be much more rigorous if they are to cause minimal inconvenience, and must deter the vehicle from being driven when the device registers that the driver’s BAC exceeds the legal limit (currently 0.08 g/dL throughout the United States).

To assess these technologies, detailed performance specifications were developed. The specifications were designed to focus the current and future development of relevant emerging and existing advanced alcohol detection technologies. In addition to requirements for a high level of accuracy and very fast time for measurement, the influences of environment, issues related to user acceptance, long-term reliability, and system maintenance are also addressed. The resulting list of specifications with definitions, measurement requirements, and acceptable performance levels are documented in the DADSS Subsystem Performance Specification Document1 . The accuracy and speed of measurement requirements adopted by the DADSS Program are much more stringent than currently available commercial alcohol measurement technologies are capable of achieving. Translating that to appropriate performance specifications was approached by calculating the potential for inconvenience if reliability, accuracy, and time for measurement were set at various levels.

This paper presents an update on the implementation of a touch-based optical sensor (TTT sensor) for monitoring the alcohol concentration in the driver of a vehicle. This novel sensor is intended to improve driver safety by providing a non-intrusive means of notifying a driver when their blood alcohol concentration may be too high to operate a vehicle safely. Details on implementation of the MARK2 system are presented along with updates on principles of the MARK3 version currently under development. Laboratory validation of the MARK2 system on standard calibration standards are presented along with discussion of next steps in validation of the technology. Updates on the demonstration vehicle implementation are also provided along with lessons learned in the implementation of the human-machine interface aspect of the design.

The National Highway Traffic Safety Administration (NHTSA) and the Automotive Coalition for Traffic Safety (ACTS) began research in February 2008 to try to find potential in-vehicle approaches to the problem of alcohol-impaired driving. Members of ACTS comprise motor vehicle manufacturers representing approximately 99 percent of light vehicle sales in the U.S. This cooperative research partnership, known as the Driver Alcohol Detection System for Safety (DADSS) Program, is exploring the feasibility, the potential benefits of, and the public policy challenges associated with a more widespread use of non-invasive technology to prevent alcohol-impaired driving. The 2008 cooperative agreement between NHTSA and ACTS for Phases I and II outlined a program of research to assess the state of detection technologies that are capable of measuring blood alcohol concentration (BAC) or Breath Alcohol Concentration (BrAC) and to support the creation and testing of prototypes and subsequent hardware that could be installed in vehicles. Phase 3, funded under the 2013 cooperative agreement (2013 CA), and subsequent phases of research, outline further refinement of the technology. It will test how the instruments might operate in a vehicle, as well as perform basic and applied research to understand human interaction with the sensors both physiologically and ergonomically. At the completion of this effort a determination will be made with respect to the devices, whether the DADSS technologies can ultimately be commercialized. This paper will outline the technological approaches and program status.

Breath alcohol screening is important for traffic safety, access control and other areas of health promotion. A family of sensor devices useful for these purposes is being developed and evaluated. This paper is focusing on algorithms for the determination of breath alcohol concentration in diluted breath samples using carbon dioxide to compensate for the dilution. The examined algorithms make use of signal averaging, weighting and personalization to reduce estimation errors. Evaluation has been performed by using data from a previously conducted human study. It is concluded that these features in combination will significantly reduce the random error compared to the signal averaging algorithm taken alone.

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