UN Regulation No. 51
Vehicle Noise Emissions

This GTR prescribes a test cycle and test procedures to measure the emissions (including off-cycle) and fuel efficiency of light-duty vehicles. The GTR was adopted at the March 2014 session of the World Forum.

A supplemental "phase 1b" is underway to refine certain elements of the initial regulation. WP.29/AC.3 expects to consider a proposal for Amend. 1 to UN GTR No. 15 in November 2016 as result of Phase 1b activities.

A second phase is expected to address low ambient temperature, high altitude test procedures, and possibly durability and conformity issues.

A third phase would eventually include the addition of reference fuels, correlation across existing regional/national cycles, and introduction of emissions limits.

The latest draft version of the amended GTR is regularly updated by the WLTP informal working group.

The regulation is also supplemented by a gearshift calculation tool. WLTP Worldwide Harmonized Light Vehicle Emissions Test Procedure GTR No. 15 GTR No. 15, Uniform Provisions Concerning the Approval of Audible Warning Devices and of Motor Vehicles with regard to their Audible Signals Audible Warning Devices Audible Warning Devices and Signals UN Regulation No. 28 UN R28, Uniform Provisions Concerning the Approval of Motor Vehicles having at least Four Wheels with regard to their Noise Emissions Vehicle Noise Vehicle Noise Emissions UN Regulation No. 51 UN R51, Uniform Provisions Concerning the Approval of Vehicles with regard to the Emission of Pollutants According to Engine Fuel Requirements Together with R49, Regulation 83 addresses vehicle emissions. R83 covers emissions from all light vehicles (M1/N1) regardless of engine type and from heavier vehicles only if equipped with a gasoline engine. Under certain circumstances, R83 or R49 can apply to light vehicle CNG/LPG engines as well as to medium passenger and commercial vehicles (M2/N2) equipped with diesel engines. R83 also contains provisions specific to hybrid variations of the vehicles under its purview. Motor Vehicle Emissions Motor Vehicle Emissions UN Regulation No. 83 UN R83, Uniform Provisions Concerning the Approval of Passenger Cars Powered by an Internal Combustion Engine Only, or Powered by a Hybrid Electric Power Train with Regard to the Measurement of the Emission of Carbon Dioxide and Fuel Consumption and/or the Measurement of Electric Energy Consumption and Electric Range, and of Categories M1 and N1 Vehicles Powered by an Electric Power Train Only with Regard to the Measurement of Electric Energy Consumption and Electric Range CO2 Emissions/Fuel Consumption Carbon Dioxide Emissions and Fuel/Energy Consumption UN Regulation No. 101 UN R101, and Uniform provisions concerning the measures to be taken against the emission of gaseous and particulate pollutants from compression-ignition engines and positive ignition engines for use in vehicles Diesel/CNG/LNG Engine Emissions Diesel and CNG/LNG Engine Emissions UN Regulation No. 49 UN R49

1. Vehicles of categories M1 and N with regard to the strength of seats and their anchorages and with regard to their head restraints;
2. Vehicles of categories M2 and M3 with regard to seats not covered by Regulation No. 80, in respect of the strength of seats and their anchorages, and in respect of their head restraints;
3. Vehicles of category M1 with regard to the design of the rear parts of seat backs and the design of devices intended to protect the occupants from the danger resulting from the displacement of luggage in a frontal impact.

It does not apply to vehicles with regard to side-facing or rearward-facing seats, or to any head restraint fitted to these seats.