Testing truck CO2 emissions

Unlike passenger cars, there is no standard EU procedure to test new truck CO2 emissions.
The European Commission has spent much of the last decade developing such a test and has called this procedure VECTO.
This test is an essential building block of for truck CO2 regulation.

What is VECTO?

Small vehicles are generally tested in a laboratory. But because of the size of trucks and the wide variety of models, laboratory testing is not really an option for large-scale testing. That’s why the Commission is following a simulation based approach. Instead of testing the whole vehicle, all components that influence CO2 or fuel economy, will be tested separately. The tires, aerodynamics, engine, transmission, weight etc are then used as an input to a software tool that can calculate CO2 emissions over typical duty cycles. This software tool is called VECTO.


Is the VECTO approach a good idea?

In principle it is a good idea to use simulation as it allows relatively accurate calculations for a great variety of vehicles. The simulation approach has been industry practice for some time and is also used in other regions such as the US and Japan. So VECTO is a good basis for regulation. But VECTO is only as strong as the input parameters it depends on. If anything is wrong with the way aerodynamics are tested, this will have a major impact on the end result, even if the software is flawless. In that sense the truck CO2 test might be subject to the same weaknesses as the passenger car CO2 tests: lack of on-road verification testing and poor oversight and control.

What needs to be done to improve VECTO?

To make VECTO more robust a few things need to happen. First of all, the test procedure needs to be complemented by an on-road full-vehicle test at the end of the process. This test would only apply to a sample of vehicles but would be used to verify that simulated and on-road performance closely matches one another. If a truck would exceed a certain threshold or tolerance (e.g. 10%) it wouldn’t pass the procedure. This procedure is somewhat similar to the real driving emissions (RDE) procedure that was introduced to measure NOx emissions in real world traffic conditions.

Secondly, it needs to be possible for (independent) third parties to check the manufacturers test results. Currently the testing system relies on type approval authorities and technical services overseeing the tests performed by manufacturers. As the Volkswagen-affair has shown, this system is far from perfect as national type approval authorities often have a cosy relationship with manufacturers. To enable third party checking, they require full access to the test procedure and the input parameters.

What is the Commission’s timeline on VECTO?

In 2016 the Commission will finalise the VECTO test and adopt it as a type approval requirement. Once adopted, truckmakers will need to start testing new trucks in accordance with the VECTO test procedure from around 2018. The type approval amendment will be introduced in comitology, not co-decision.

In 2017 the Commission will make a proposal to legally oblige truckmakers and member states to report these VECTO test results to the EU. The so-called Monitoring, Reporting and Verification proposal will be a legislative proposal and needs to be approved by Parliament and Council. Member states will likely have to report this data to the Commission as from 2018/19.

Since the VECTO procedure does not currently cover all truck categories (and technologies) the Commission will continue working on the completion of specific test procedures for buses and small urban trucks. At some point the Commission should also start working on a procedure to test trailer performance.

Contact our experts:

William Todts

Director, Freight and Climate
+32 (0)495 799 505

Stef Cornelis

Safer and Cleaner Trucks Officer
+32 (0)484 27 71 91 s

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