Proposal to allow for the use of natural gas refrigeration systems to vehicles propelled by natural gas (CNG or LNG). This proposal addresses a new, environmentally friendly natural gas fuelled refrigeration system for trucks with refrigerated loads that already are propelled by natural gas. Currently paragraph 18.1.7.1 allows heating systems to be fitted on vehicles to heat the passenger compartment and/or the load area of a vehicle, however, the same provision omits cooling systems that are used on trucks for the carriage of loads requiring refrigeration.