Following the agreement reached at the fifty-fourth GRPE session , seven informal meetings were held prior to the proper session of the fifty-fifth GRPE . The third informal meeting of the GRPE working group on Hydrogen and Fuel Cell Vehicles - Subgroup Environment ( HFCV-SGE ) was held on 14 January 2008 ( afternoon only ) under the Chairmanship of Mr. A. Perujo ( EC ) .