Alcohol Countermeasure Systems (International) Inc., commonly known as ACS, is an international group of companies with one common purpose: to promote road safety through industry-leading breath alcohol testing technology.

ACS began as a research division of Borg-Warner in 1970 with the mandate to develop a technology that would prevent the operation of a vehicle by a drunk driver. The research was successful and in 1976 the group was incorporated as Alcohol Countermeasure Systems in Canada and the USA. This life saving innovation became known as the breath alcohol ignition interlock device (BAIID or IID).