This invention relates to a system and method that can quickly and accurately detect and measure ethyl alcohol in the blood of a motorized vehicle driver transdermally and non-invasively within minutes of ethanol consumption and in the presence of interferents. The system includes an array of sensors embedded into the steering mechanism of a motorized vehicle, a data base of patterns produced through empirical testing of various analytes in various combinations and concentrations, neural net based pattern recognition algorithms to ascertain the driver's transdermal alcohol concentration and a database derived from human testing, correlating the driver's transdermal alcohol concentration with the driver's blood alcohol concentration. The detection system is integrated with a motor vehicle decision module which can prevent the operation of a motorized vehicle by a driver whose BAC exceeds a preset limit.