Proposal (revised from its earlier version) to allow horn sound level testing with the engine running and lower the sound pressure level requirement for light-duty vehicles from 93 dB (A) to 90 dB (A).

Testing and Evaluation of the variant method using the dω/dt form.

Text prepared by the GRB Expert Group on Regulation 51 and revised during the GRB-59 session consolidating the proposed 03 series of amendments to UN Regulation No 51 developed during the informal group’s fourth meeting in Brussels on July 4 plus additions from November 8. This version removes references to “acoustic vehicle alerting systems” (AVAS)