Topics / From Laboratory to Road

The Lab to Road project, begun in 2012, documents the widening gap between official vehicle CO2 emissions and real-world CO2 emissions in Europe. As the papers in this series have shown, that gap grew from about 9% in 2001 to well over 40% in 2015. The series also identifies a number of reasons for the increasing gap, including flexibilities in the type-approval procedure that allow for unrealistically low driving resistances and unrepresentative conditions during laboratory testing; fuel-saving technologies such as stop/start systems and hybrid powertrains that prove more effective at reducing CO2 emissions during laboratory testing than during real-world driving; and failure to take into consideration auxiliary devices such as air conditioning and entertainment systems in the type-approval process.

This multi-year project shows the urgent need for improved test procedures. The Worldwide Harmonized Light Vehicle Test Procedure (WLTP) will help but cannot close the gap alone. On-road tests, similar to the Real Driving Emissions (RDE) test procedure for air pollutants, and in-use conformity tests of randomly selected production vehicles should also be introduced.

Most Recent

This update adds one new data source, for a total of 14, covering 16 years, eight countries, and approximately 1.1 million cars. The analysis shows that, in the EU, the gap between official and real-world CO2 emission values continues to grow—from 9% in 2001 to 42% in 2016.

Investigates the gap between real-world and official CO2 emission values in the four largest vehicle markets in the world: China, the EU, Japan, and the United States. The analysis shows that the gap has increased in all markets since 2001. 

This update adds two new data sources, for a total of 13, covering 15 years, six countries, and approximately 1 million cars. The analysis shows that, in the EU, the gap between official and real-world CO2 emission values continues to grow—from 9% in 2001 to 42% in 2015.

2017.11.05

This update adds one new data source, for a total of 14, covering 16 years, eight countries, and approximately 1.1 million cars. The analysis shows that, in the EU, the gap between official and real-world CO2 emission values continues to grow—from 9% in 2001 to 42% in 2016.

Publication: White paper
2017.11.05

Investigates the gap between real-world and official CO2 emission values in the four largest vehicle markets in the world: China, the EU, Japan, and the United States. The analysis shows that the gap has increased in all markets since 2001. 

Publication: White paper
2016.11.16

This update adds two new data sources, for a total of 13, covering 15 years, six countries, and approximately 1 million cars. The analysis shows that, in the EU, the gap between official and real-world CO2 emission values continues to grow—from 9% in 2001 to 42% in 2015.

Publication: White paper
2015.09.24

This annual update to the L2R series analyzes eleven data sources covering fourteen years, six countries, and almost 600,000 vehicles. In the EU the gap between official and real-world vehicle CO2 emissions grew to 38 percent in 2014.

Publication: White paper
2014.09.28

Extends an analysis of the gap between official and real-world fuel consumption and CO2 emissions for passenger cars in Europe, which reached 38% in 2013 and continues to grow at an accelerated pace.

Publication: White paper
2013.05.27

Comparison of official and "real-world" fuel consumption and CO2 emission values for passenger cars in Europe and the United States, which shows that the average discrepancy between them rose from less than 10% in 2001 to 25% in 2011.

Publication: White paper