The prevention of 8,300 premature deaths, more than 9,500 hospitalizations, and 1.5 million lost work days are just a few of the substantial benefits the Environmental Protection Agency (EPA) hopes to realize by reducing annual vehicle emissions with its recent onboard diagnostics (OBD) requirement. Formally approved Dec. 4, the ruling seeks to reduce overall diesel emissions by more than 90 percent through a 2010 mandate requiring heavy-duty truck manufacturers to install OBD technology. 

Designed to monitor performance of an engine's major components, the built-in, computer-based systems will provide a simple, quick, and effective way to alert drivers when engine emission systems are malfunctioning or deteriorating, according to the EPA. 

The Air Resources Board (ARB) reported 33 states and local areas have already begun incorporating the use of onboard diagnostics to comply with the Clean Air Act's goal of reducing air pollutant emissions, a number surely to expand over the next year with the EPA's new rule. 

Cleaning is 'Greening'

In September, with OBD considered a critical element in an overall emissions control program, the EPA worked with the State of California to finalize a consistent set of heavy-duty onboard diagnostic (HDOBD) requirements. As a result, the EPA's HDOBD program largely resembles the California program in almost all important aspects. 

The EPA requirement will provide truckers dashboard malfunction indicator lights and diagnostic trouble codes similar to those on passenger vehicles since the mid-'90s. A provision in the rule also requires manufacturers to make available to mechanics information necessary to perform repairs and maintenance service on OBD systems and related components. 

The highly technical and detailed 475-page rule applies to 2010 and later model-year engines and will be phased in gradually. Beginning in 2010, engine manufacturers will be required to produce one engine line for heavy-duty trucks that complies with the new rule. By 2013, the dashboard lights will be mandatory for all highway engines. 

Without the warning device, a driver could easily overlook emission problems, the EPA regulation stated. 

Despite concerns from groups such as the Engine Manufacturers Association that meeting the OBD requirements would present challenges, the EPA said sensors needed to comply with the requirements already are available and will exist in time for 2013 compliance. In addition, the EPA said it will "keep abreast of technological advances in the coming years" in the event the requirements must be modified.

To find out which areas require OBD technology in vehicle emissions tests, go to