Have car manufacturers been doctoring their emissions?


Exhaust emissions

Car manufacturers have been accused of making their cars’ emissions appear lower than they really are.

In a report published by the European Commission (EC), car makers have been accused of underestimating the CO2 figures emitted during real-world driving conditions by as much as 11 per cent.

According to the report, there are a number of modifications that manufacturers use to portray lower figures, including taping up gaps in the body to lower the car’s drag, and using smaller wheels to optimize rolling resistance.

Pre-conditioning cars before testing was found to be another ‘tweak’, involving making sure certain components are fully warmed up.

It also claims that manufacturers regularly refrain from using their own test track, instead opting to use the same track in Spain to test vehicles. The Spanish track has the best conditions for testing coasting data, including ambient temperature and a downward slope that provides minimal aerodynamic drag.

But now the EC is calling for action, with a spokesman stating the findings have been presented to the World Light-Duty Test Procedure (EU-WLTP) in order to develop a new global test.

“This is about assessing exactly how much individual vehicles emit so consumers and legislators have reliable information,” he explained.

While the report doesn’t single out any specific manufacturer, it suggests these tactics are being used throughout the industry.