We are establishing a manufacturer-run, in-use emissions testing program for 2007 and later model year heavy-duty diesel vehicles. The ground-breaking in-use test program will require engine manufacturers to measure exhaust emissions from their diesel engines using portable emissions measurement systems. Also for the first time, all manufacturers will be regularly providing EPA with a significant quantity of emissions data generated from engines used in regular service, which EPA will evaluate to ensure the engines comply with specified emissions requirements. The rule is a result of an agreement between EPA and the Engine Manufacturers Association. This rule advances EPA's clean diesel activities by helping to ensure that the benefits of more stringent emission standards are realized under real- world driving conditions.