In FY 2008, Federal and State enforcement personnel conducted 14,906 compliance reviews (CRs) on individual motor carriers. It is intended that through education, heightened safety regulation awareness, and the enforcement effects of the CR, carriers will improve the safety of their commercial vehicle operations and, ultimately, reduce the number and severity of crashes in which they are involved. The CR Effectiveness Model measures the direct impact of compliance reviews on carriers that received CRs but not the "deterrent" effects (i.e., the "threat" of having a CR) on carriers that did not actually receive CRs. The model is based on the individual and cumulative "before and after" changes in the safety performance of carriers that received CRs in a given year. The model compares a motor carrier's crash rate in the 12 months following an onsite compliance review to its crash rate in the 12 months prior to that review. The model uses crash data reported by the States and power unit data reported by carriers or obtained during CRs to calculate both the before-CR and after-CR crash rates. This report documents the benefits derived from performing CRs on motor carriers in terms of crashes avoided, as well as lives saved and injuries prevented.