| GTR No. 4 WHDC | Worldwide Heavy-Duty Vehicle Emissions Certification Procedure | Global Technical Regulation No. 4: Test Procedure for Compression-ignition (C.I.) Engines and Positive-ignition (P.I.) Engines Fuelled with Natural Gas (NG) or Liquefied Petroleum Gas (LPG) with regard to the Emission of Pollutants The Informal Group on Heavy-Duty Hybrids expects to deliver its final draft amendment to GTR No.4 at the January 2014 session of GRPE. This amendment would extend GTR No. 4 to include test procedures to evaluate hybrid heavy-duty vehicles. WHDC Worldwide Heavy-Duty Vehicle Emissions Certification Procedure GTR No. 4 GTR No. 4 | GTR | 4 | |
| GTR No. 11 NRMM Emissions | Non-Road Mobile Machinery Emissions | Test procedure for compression-ignition engines to be installed in agricultural and forestry tractors and in non-road mobile machinery with regard to the emissions of pollutants by the engine NRMM Emissions Non-Road Mobile Machinery Emissions GTR No. 11 GTR No. 11 | GTR | 11 |