Questions raised over car makers' emissions tests

Emissions tests questioned
21 Feb, 2013 4:36pm Claire Holden

The European Commission has accused manufacturers of manipulating official emissions testing to get better results

Car manufacturers have been accused of manipulating official testing methods to make their cars seem as though they have lower emissions figures than they actually do.

A report published by the European Commission claims that manufacturers could have doctored their testing methods, resulting in CO2 figures that are as much as 11 per cent lower than in real-world driving conditions.

The reports claims that there are a number of ‘tweaks’ to the testing method used to portray a lower emission figure, such as using smaller wheels to optimise rolling resistance and fuel economy. Testing a car with a fully charged battery was also cited as leading to a lower emissions reading.

The report also said that manufacturers regularly use the same track in Spain to test vehicles, instead of their own test track, because it had optimum conditions for testing coasting data such as a downward slope, ambient conditions and minimal aerodynamic drag.

The report could also have implications on the industry as it points out where regulations allow for discrepancies. It also mentions that while tests must be carried out in two opposite directions, it does not state that this has to be on the same road, consequently both directions of the track might be downhill.

Manufacturers were also found to precondition their cars before testing, ensuring certain components are fully warmed up and sealing any gaps between body parts by taping them up to help lower the vehicle's resistance.

While the report does not single out any specific manufacturer, it does suggest that these tactics are being used throughout the industry.

What do you make of the European Commision's report? Does fiddling the results bother you if it means you're paying less road tax? Or should all manufacturers come clean with the true figures? Tell us your thoughts in the comments section below.