The Diesel Engine Flexibility Act aims to provide regulatory stability for motor vehicles and engines, including both on-road and nonroad vehicles. By establishing a clear framework for emissions standards, the legislation seeks to reduce uncertainty for manufacturers and operators, allowing them to plan their operations without the fear of sudden regulatory changes. A key provision of the Act is the establishment of a ten-year period during which the Environmental Protection Agency (EPA) cannot impose stricter emissions standards than those set in 2007 and 2010.