Gap Grows Between European Test and Real-World Fuel Economy

The shortfall between Europe's fuel economy ratings and actual fuel consumption has expanded from 8% in 2001 to 21% today, according to the International Council on Clean Transport.

The nonprofit ICCT warns that further widening of the gap may discourage consumers from paying for new fuel-saving technologies.

The analysis blames unrealistic test conditions allowed by the New European Driving Cycle (NEDC) procedure. Among them are a "cold start" at 85 F, low acceleration rates, below-normal test weights and a large proportion of steady-state throttle conditions all of which reduce fuel consumption. Similarly, the ICCT complains that testing is conducted with all power-consuming accessories such as air conditioning turned off.

The ICCT says a stronger connection between test results and actual emissions will be critical to meet future European Union targets. The EU requires the region's transportation sector to cut its greenhouse gas emissions about 90% by 2050 compared with 1990 levels.

Europe's carmakers agreed in 1999 to achieve a voluntary average of 140 g/km of carbon dioxide by 2008 but failed to meet that goal. In 2009 the EU mandated a CO₂ reduction to 130 g/km by 2015. The report notes that the European average CO₂ emission level last year for new vehicles was 140.3 g/km.

The EU plans to replace the current NEDC test with the World Harmonized Light-Duty Vehicle Test Procedure after 2015. The ICCT urges independent vehicle monitoring of emission reductions to ensure that new test more closely aligns with real-world vehicle performance.

The full ICCT report can be downloaded HERE.