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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The reported work is highly related to the DADSS (driver alcohol detection system for safety, [3]) program, and other related initiatives aiming at the prevention of drunk driving. The possibility of breath alcohol estimation in highly diluted breath samples in a vehicle cabin by using carbon dioxide as a tracer gas to compensate for the dilution has been demonstrated and evaluated elsewhere [4-12]. The infrared sensor technology developed by SenseAir AB, Sweden, is enabling unprecedented sensor performance [9]. However, passive breath alcohol detection requiring no cooperation from the driver has remained a major technological challenge. The aim of the present investigation is to obtain experimental proof-ofprinciple of completely passive, in-vehicle estimation of breath alcohol concentration. A prototype sensor system has been integrated with the casing of the upper steering column within a vehicle. Human subjects, some of them intoxicated by alcohol, are instructed to enter the vehicle and perform a simulated driving task while breathing normally. Sensor signals corresponding to alcohol and CO2 concentration at the sensor position are recorded and analyzed off-line. The sensor CO2 signal pattern includes peaks corresponding to increasing CO2 concentration in expired air reaching the sensor position after leaving the subject’s mouth or nose. These peaks will coincide with peaks in the alcohol signal from an intoxicated subject. From the peak magnitudes an algorithm for breath alcohol estimation has been devised. The results indicate that peaks from normal breathing are readily detectable and quantifiable by the sensors, although the dilution factor DF (ratio between expired and actual concentration measured by the sensor) may be as high as several hundred at the steering column sensor position.

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Although the vast majority of vehicle drivers are sober, drunk driving remains to be a major contributor to fatal accidents. Massive deployment of unobtrusive breath alcohol sensing systems could potentially save tens of thousands of lives worldwide every year by preventing drunk driving [1]. The work reported here is ultimately aiming at such a system. The technical performance of the present sensing system with respect to automotive requirements is summarized, and new results towards unobtrusive breath alcohol determination within vehicle compartments are presented.

Breath alcohol concentration (BrAC) can be determined unobtrusively if (i) the sensing system provides real-time signals with adequate accuracy corresponding to the local concentrations of both alcohol and a tracer gas, e g CO2, (ii) the dilution of the breath is not excessive in relation to background concentrations, (iii) the sensor location can be seamlessly integrated into the interior of a vehicle cabin. All three of these aspects are addressed in the present paper.

More than a hundred prototypes based on infrared spectroscopy were fabricated and subjected to automotive qualification tests in the full temperature range -40 … +85⁰C. In the majority of tests, adequate performance was noted. Measures are now being taken to fill remaining performance gaps. Test results with human subjects were positive and in accordance with expectations with respect to physiological variations. In-vehicle tests showed that for the best sensor position, passive breath samples allowed BrAC to be determined at a resolution of 2-4% of the US legal limit, providing proof-of-principle for unobtrusive testing. Nevertheless, vehicle integration remains to be the major technological challenge to the objective of deployment on a large scale of unobtrusive driver breath alcohol determination.

The feasibility of unobtrusive breath alcohol determination in vehicles, and adequate performance of a sensor system based on infrared spectroscopy have been experimentally demonstrated. The alcohol sensing system may advantageously be integrated into vehicles, and may also be combined with other technologies to monitor driver impairment.