Action
Direct final rule.
Summary
EPA and NHTSA, on behalf of the Department of Transportation, are each adopting corrections to provisions in our respective Medium- and Heavy-Duty Greenhouse Gas Emissions and Fuel Efficiency final rule issued on September 15, 2011. These amendments eliminate duplicative reporting requirements, reduce inadvertent minor differences between the EPA and NHTSA programs regarding such matters as voluntary early model year compliance, better align testing procedures to market realities, and reduce unnecessary testing burdens. This action also separately amends several regulations exclusive to EPA by: adjusting the provisions of the replacement engine exemption, expanding EPA's discretion to allow greater flexibility under the Transition Program for Equipment Manufacturers related to the Tier 4 standards for nonroad diesel engines, specifying multiple versions of the applicable SAE standard for demonstrating that fuel lines for nonroad spark-ignition engines above 19 kilowatts meet permeation requirements, and allowing for the use of the ethanol-based test fuel specified by the California Air Resources Board for nonroad spark-ignition engines at or below 19 kilowatts. Some of the individual EPA-only provisions of this action may have minor impacts on the costs and emission reductions of the underlying regulatory programs amended in this action, though in most cases these are simple technical amendments. For those provisions that may have a minor impact on the costs or benefits of the amended regulatory program, any potential impacts would be small and we have not attempted to quantify the potential changes.