Touch Technology

The DADSS Program is working on a new approach to measuring blood alcohol concentration: a touch system that uses tissue spectroscopy to measure alcohol in the driver’s finger or palmar side of the hand. This technology significantly broadens the options for integrating such a system into commercial vehicles while remaining invisible to any driver under the legal limit. Tissue spectroscopy was identified in 2007 as one of the most promising technologies to seamlessly and reliably detect and prevent drunk driving in vehicles and remains so today.

How It Works

The touch system is being designed to analyze alcohol found beneath the driver’s skin’s surface (or more specifically, the blood alcohol content detected in the capillaries). Measurement begins by shining an infrared light on the driver’s skin, similar to a low power flashlight, which moves into the tissue. A portion of the light is reflected back to the skin’s surface, where it is collected by the touch pad. This light contains information on the skin’s unique chemical properties, including the concentration of alcohol.

There are two discrete wavelength sources that signal the presence of alcohol. To ensure the speed, accuracy and precision of the device, the touch system doesn’t analyze all wavelengths – it focuses precisely at the wavelengths where alcohol can be found. In order for the system to operate seamlessly for the driver, it must be able to take multiple readings in a matter of sections.

Testing The Prototype

During its initial phase, the Program created a touch-based standard calibration device that combines a series of eight compounds to accurately simulate the composition and density of tissue in a finger. The prototypes were then put through a series of human subject tests, comparing prototype readings to blood sample readings, as well as durability tests in different environmental situations. These tests continue today. Since developing the first prototype, program engineers have successfully reduced the size of the touch sensor by 89%. They are now moving toward integrating a touch protype into a vehicle for the next phase of testing. Once integrated, data will be collected to allow engineers to further refine the sensor to ensure the highest levels of speed, accuracy, and precision.

Vehicle Integration

Current design elements for the touch technology call for installation in an area that is natural to the driver, such as the vehicle start button, gear shift or steering wheel. Program engineers are also working to ensure the touch technology can accurately detect if it is not the driver using the touchpad. One possibility is that the technology will use driver presence detectors in the front seat, which would generate a low-level signal when the driver is seated. When the driver presses the stop/start button or wherever the sensor is located, the driver completes the loop and confirms that he or she is the person touching the button. If anyone not in the driver seat presses the button, the circuit will not be closed and the alcohol measurement will not be considered valid, and the system may ask for a re-test.