Direct Final Rule Amending the Test Procedures for Heavy-Duty Engines, and Light-Duty Vehicles and Trucks and the Amending of Emission Standard Provisions for Gaseous Fueled Vehicles and Engines

This action promulgates amendments to several sections of the heavy-duty engine test procedure regulations in 40 CFR part 86. These changes are needed in order to accommodate the use of new testing equipment, to provide greater flexibility in the type of testing equipment used and to ensure uniform calibration and use of the testing equipment. The amendments will ensure the continued validity of testing results and ensure that heavy-duty engines are being exercised appropriately over the test procedures. This action also makes limited changes to the light-duty vehicle and truck test procedure regulations and the gaseous fuel emission standards in 40 CFR part 86. Because changes are limited to technical issues, all of which have been coordinated with industry, EPA expects no adverse comments.