Verification Procedure - Background

This page last reviewed October 29, 2007.


Verification or Certification... What's the difference?

ARB has several programs relating to sale, use, or modification of emission control systems. The programs are specific to the type of device as well as the market for which it was designed. The information below outlines the various programs. For more detailed information, please click on the individual link below.An exemption is necessary for the sale of After-Market Parts if they are to be sold or used inCalifornia: To improve air quality, the California Air Resources Board (ARB) requires vehicle manufacturers to develop engine and emission equipment systems that reduce the specific pollutants that cause California's severe air quality problem.

These emission control systems are also required to be proven durable and reliable. To ensure that these systems operate as designed, California Vehicle Code Section 27156 and the Federal Clean Air Act prohibit modifications to these systems that increase motor vehicle emissions. Since if properly designed, most performance modifications do not increase vehicle emissions, these same laws also allow the installation of parts or modifications proven by their manufacturers and certified by the ARB not to increase vehicle emissions. For information on the exemption and other Aftermarket Parts Related Programs.

The Verification Procedure provides a way to thoroughly evaluate the PM emission reduction capabilities and durability of a variety of diesel emission control strategies as part of a retrofit in-use program. It ensures that emission reductions achieved by a control strategy are both real and durable and that production units in the field are achieving emission reductions which are consistent with their verification. The verification program supports the ARB's Diesel Risk Reduction Plan. Information on the Verification Process.

Certification requires that new motor vehicles and engines must be certified by the ARB for emission compliance before they are legal for sale, use, or registration in California. Certification is granted annually to individual engine families and is good for one model year. An engine family is a grouping of vehicles or engine models that exhibit similar emission characteristics (e.g., common engine parameters, fuel system, and emission control systems). Within an engine family, there may be one or more evaporative families that are associated with distinct vehicle models. For information on the Certification Process.

OTHER FEDERAL PROGRAMS U.S. EPA's Voluntary Diesel Retrofit Program:U.S EPA has developed the Voluntary Diesel Retrofit Program to help make a difference in the immediate future. The program will address pollution from diesel construction equipment and heavy-duty vehicles that are currently on the road today. Further Information.

U.S. EPA's Environmental Technology Verification (ETV) Program develops testing protocols and verifies the performance of innovative technologies that have the potential to improve protection of human health and the environment. ETV was created to accelerate the entrance of new environmental technologies into the domestic and international marketplace. Additional Information.