The issues surrounding the Tier Four compliance engine emissions requirements for OEMs and enforcement by the California Air Resources Board (CARB) are certainly worth the amount of coverage you offered in your publication ("Market Tries to Turn Used Yellow into Green," April 2008).
It's very difficult to adequately cover the complex engineering and manufacturing issues woven through the story. One reason is that there is no "one-size-fits-all" solution to such regulatory challenges facing equipment manufacturers. The equipment-manufacturing industry has invested heavily and made great strides in reducing emissions associated with the operation of off-road machines, and these efforts really deserve a closer and more detailed examination. A close look at the very challenging undertaking of retrofitting to meet new and increasingly more stringent regulatory requirements requires a systems approach involving not only engines, but fuel and other con-siderations. Equipment and operator safety is also a manufacturing value — visibility, heat transfer, ease of maintenance are all major concerns. Members of the Association of Equipment Manufacturers remain committed to reducing emissions, improving the environment, and providing the lowest emissions-emitting machines that the customer will buy.