<prompt> Translate the following text to EnglishKutumia muundo wa lag uliotumika katika RIAs ya Tier 2 ya Gasoline Sulfur na Injini za Kazi Nzito na kuidhinishwa na SAB EPA-SAB-COUNCIL-ADV-001, 1999, tunadhani muundo wa lag ya miaka mitano.  <response>: Adopting the lag structure used in the Tier 2Gasoline Sulfur and Heavy-Duty EngineDiesel Fuel RIAs and endorsed by the SAB EPA-SAB-COUNCIL-ADV-00-001, 1999, we assume a five-year lag structure. 