The DADSS research and development effort is following a two-stage process. The Phase I effort, now complete, focused on the development of working proof-of-principle prototypes. Phase II is the major development effort that will lead to a research vehicle that will demonstrate the technologies.
The first tasks to be undertaken in Phase I included a comprehensive review of emerging and existing state-of-the-art technologies for alcohol detection and the development of performance specifications. Two technology approaches were chosen for Phase I development; Tissue Spectrometry Systems (touch-based) and Distant/or Offset Spectrometry Systems (breath-based).
- Tissue Spectrometry is a noninvasive approach that utilizes the near infrared region of the electromagnetic spectrum (from about 0.7 μm to 2.5 μm) to measure substances of interest in bodily tissue. The measurement begins when the driver touches a sensor which illuminates the user’s skin with NIR light which propagates into the tissue. The beam of light can penetrate tissue at depths of up to 5 mm to reach the dermal layer where alcohol that is dissolved in water resides. A portion of the light is diffusely reflected back to the skin’s surface and collected by an optical touch pad. The light contains information on the unique chemical information and tissue structure of the user. This light is analyzed to determine the alcohol concentration and, when applicable, verify the identity of the user.
- Breath-based, or Distant Spectrometry Systems use an approach similar to tissue spectrometry, in that they utilize the mid infrared (MIR) region of the electromagnetic spectrum (2.5-25 μm); however no skin contact is required. Breath-based approaches are designed to remotely analyze alcohol in a driver’s breath within the vehicle cabin without the driver having to specifically provide a deep-lung breath sample. The working principle of the sensor is to use measurements of expired carbon dioxide (CO2) as an indication of the degree of dilution of the alcohol in expired air. Normal concentration of CO2 in ambient air is close to zero. Furthermore, CO2 concentration in alveolar air is both known and predictable, and remarkably constant. Thus, by simultaneously measuring CO2 and alcohol, the degree of dilution can be compensated for using a mathematical algorithm.
The specific objective for Phase I was to develop prototypes intended to represent devices capable of rapidly and accurately measuring the driver’s BAC non-intrusively. The prototypes, which were required to address just the accuracy, precision, and speed of measurement specifications, did not attempt to simulate the visual appearance, choice of materials or intended manufacturing process. The overall aim was to validate the potential design approach, as well as point to areas where further development and testing may be necessary. The Phase I development comprised a 12-month period of performance and involved three companies. Two companies, Autoliv Development AB and Alcohol Countermeasure Systems (ACS) were chosen to develop prototypes that used the breath-based approach, and TruTouch Technologies was chosen to develop a prototype that used the touch-based approach.
Based on the results of testing, one touch-based approach under development by Takata TruTouch Automotive Solutions, and one breath-based approach by Autoliv Development AB are judged to have the potential with future development to measure BAC quickly, and with high levels of accuracy and precision. These companies commenced Phase II development during the third quarter of 2011. The Phase II development stage, which will span two years, will have a research vehicle available by the end of 2013 that will demonstrate both of these technologies.