Under the current 04 series of amendments to UN Regulation No. 41, the engine speed should be measured during all tests in Annex 3 and Annex 7 (Additional sound emission provisions – ASEP). However, IMMA has found that there is very little difference between the measured and the calculated engine speed for a manual transmission (MT) vehicle (Annex, figure 1) and no impact on the test result (Annex, figure 2). Therefore, this proposal would introduce a calculated engine speed for MT vehicles and for continuously variable transmission (CVT)/automatic transmission (AT) with locked gear mechanism into UN Regulation No. 41.