Editors' Summary: EPA imposes strict emissions and durability standards on vehicle manufacturers today. While these standards have become more stringent over time, the regulatory requirements for demonstrating compliance with these standards have relaxed. In this Article, Kevin L. Fast identifies and describes this relevant regulatory framework governing the reporting of emission-related component defects in North America. He provides descriptions and data on nearly 600 defect reports prepared by 6 of the largest vehicle manufacturers currently in the marketplace. Finally, he provides a comparative analysis linking the results of his data analysis to other regulatory programs for monitoring the in-use performance of motor vehicles.