The WLTP test is a huge improvement over NEDC, the obsolete test it replaces. However, the WLTP is still a laboratory test and does not accurately represent real-world emissions that are estimated to be 23% higher, said sustainable transport group Transport & Environment (T&E).
The RDE test will make a significant contribution to lowering diesel NOx emissions and particulate emissions from gasoline cars. It is a real-world test in which the emissions are measured using a portable emissions monitoring system.
Greg Archer, director of clean vehicles at T&E, said: “The introduction of the WLTP and RDE tests marks an important milestone in the battle to ensure cars comply with environmental limits on the road and to end the cheating that has become endemic in emissions testing. But new tests are not a panacea and will need to be further refined to ensure they are really representative of how cars are driven. The forthcoming decisions on how and who approves cars for sale will be key to ensuring the system of approvals is independent and rigorously enforced."
Greg Archer concluded: "The new tests will only help clean up our toxic air and tackle climate change if there are new, tighter emissions standards. The EU is moving in the right direction but much still must be done to bring an end to dirty diesels and gasoline-guzzling cars."