New injury control technologies are continually emerging in the automotive marketplace. Insertion mechanisms and rates vary based on the complexity and stability of the technology, the cycle of new vehicle and platform introductions, and consumer acceptance. The injury control effectiveness of newly emerging technologies is assessed based upon changes recorded in collision related injury and fatality data from US Federal and State motor vehicle collision databases. This analysis provides an assessment of side impact air bag (SIAB) effectiveness based upon data from the Fatality Analysis Reporting System (FARS). The study considers vehicle models over the time period 1998 to 2008 that converted from having no side impact air bags available to having side impact air bags as standard equipment. Distinctions are made between two types of side impact air bags: torso (or thorax) side air bags and roof rail mounted head curtain air bags. Estimates of effectiveness are based on comparisons of fatality rates for the 2 years prior to insertion of the injury control technology and 2 years following insertion in each model pair.