INTRODUCTION AND SUMMARY This report summarizes the results obtained during the first year of the Extended Phase I CRC Emission Test Program. The main focus of this study was to assess the feasibility of reducing exhaust emissions through a program of mandatory inspection and maintenance. The basic differences between this analysis and one presented in the Interim Report [1] involve the use of an improved experimental data base and refinements in the Economic Effectiveness Model. A detailed account of the derived emission data sets is presented in Volumes IV and V. A corresponding discussion of the structure and elements of the model is given in the Economic Effectiveness model Handbook (Volume III). The Study was conducted using the Economic Effectiveness Computer model program which is capable of predicting the emissions changes and costs associated with a wide range of inspection and maintenance procedures.