The National Highway Traffic Safety Administration published a notice in the Federal Register August 24 denying Plant Oil Powered Diesel Fuel System Incorporated’s petition to revise the joint fuel economy and greenhouse gas emissions standards for medium- and heavy-duty trucks. The company, which manufactures systems to enable diesel engines to run on vegetable oil, claimed in a February 27 petition that the Department of Transportation and the Environmental Protection Agency had excluded the company’s technology when they established the standards. The administration denied the petition because including vegetable oil diesel engines in the analysis would have resulted in different standards.