First real-world car CO2 results show gap of up to 56%

The very first tests of cars’ ‘real-world’ CO2 emissions have revealed gaps between official and actual emissions of 36-56% – very similar to those of other on-road fuel efficiency databases. Three models were tested by PSA Peugeot Citroën, under a protocol devised with T&E, on public roads near Paris with passengers, luggage loads, use of air conditioning and other real-life driving conditions.


When tested a Peugeot 308 1.6l diesel model recorded a fuel efficiency rating of 5.0 litres per 100 km, or 20 km/l, compared to just 3.2 litres in the official NEDC tests. A Citroën Grand C4 Picasso delivered 5.6 l/100 km (17.8 km/l) in real-world conditions, compared to 4.0 litres in the official tests. The DS3 model consumed 4.9l/100km (20.4 km/l) versus 3.6 litres in the NEDC tests. By the summer the French group will publish the actual consumption of 30 models from the Peugeot and Citroen ranges.

PSA Peugeot Citroën is the first carmaker to carry out such tests and the first results are comparable to those obtained from independent customer surveys. T&E says this shows that the procedure conducted is scientifically robust and representative of a typical driver.

Greg Archer, T&E’s clean vehicles director, said: “The test developed with PSA Peugeot Citroën is reproducible and representative. It confirms the fuel consumption of a tested model by a typical driver in real-world driving conditions. This test proves that the on-road tests are reliable and can be used to measure real CO2 emissions. This should become the benchmark for all carmakers advertising their vehicles’ fuel efficiency.”

The results of the protocol will be presented to the European Commission with a view to real-world driving conditions being accounted for in the next revision of Europe’s car CO2 standards.

Similar the EU’s real-driving emissions (RDE) measurements, the protocol measures fuel consumption by means of a portable emissions measurement system (PEMS) installed on the vehicle. The results are checked by independent auditors Bureau Veritas. PSA and T&E plan to conduct real-driving emissions tests for NOx by spring 2017.

PSA also said one other carmaker had approached it to know more about the real-world testing protocol but the company declined to give further details.