Guidance for On-Road Testing Requirements for Enhanced Vehicle Inspection and Maintenance (I/M) Programs

This guidance was developed to clarify how the on-road testing requirement can be met in states with mandatory enhanced vehicle emission inspection and maintenance (I/M) programs. On-road testing is a necessary element of an I/M program that is required by the Clean Air Act (CAA) to be operated at the enhanced performance level. On-road testing involves the collection of emissions data from a sample of subject in-use vehicles within an enhanced I/M program. The analysis of data obtained from on-road testing can be useful in assessing the effectiveness of an I/M program.

In support of efforts to increase compliance, the Environmental Protection Agency (EPA) developed this guidance to help state and local governments meet their CAA and regulatory requirements in enhanced I/M program areas. This guidance also provides options and reflects the latest technologies and practices in use by enhanced I/M programs across the United States. Finally, this guidance was written as a result of a 2018 audit by the Office of Inspector General (OIG) regarding EPA oversight of enhanced I/M programs, entitled, Collecting Additional Performance Data from States Could Help EPA Better Assess the Effectiveness of Vehicle Inspection and Maintenance Programs (OPE-FY17-0018).