25. GRB noted that WP.29, at its March 2009 session, had endorsed the proposal to set up an informal group on Minimum Sound Levels for silent vehicles (MSL). The expert from Japan introduced GRB-50-08 regarding a study on approach audible systems for hybrid and electric vehicles. He also presented a number of sample sounds (steady and non-steady) for approaching silent vehicles. The expert from the United States of America stressed the need that such sounds should not only be similar to that emitted by combustion engine, but also indicate the speed, direction as well as the acceleration or deceleration of the vehicle. He recalled that this information was important, especially for visually-impaired people.