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.