Advice: Fuel consumption and WLTP - how meaningful are the new details?

Since September 2017, new cars in Germany have only been registered if CO2 emissions and fuel consumption after WLTP test method determined and specified.

According to the ADAC, the Results be more realistic than with the NEDC procedure previously used.

After almost 3 years, we would like to gather some information on the measurement process and the effects of WLTP (Worldwide Harmonized Light Duty Test) and, at the end of the guide, take a critical look at the meaning and accuracy of this new information.

How is WLTP measured?

1. In contrast to the old NEDC procedure, the WLTP test now takes 20 minutes instead of 10 minutes.
2. The test route traveled (previously 11 kilometers) is extended to 23,25 km.
3. The temperature spectra are narrowed down (keyword cold start) and load conditions also play a role.
4. An incident like the diesel scandal should of course not happen again, so RDE (Real Drive Emissions) tests are now being carried out.

What is affected by WLTP?

Basically, the consumer could look forward to a more transparent and better method for measuring consumption and exhaust gas based on the list above.

However, the changeover for motorists and car buyers has also created a lot of confusion (the vehicle tax differs in some cases for completely identical models only because of the registration date) - and drivers are of course skeptical when it comes to emissions figures, as far as the transparency of manufacturers is concerned.

Have the consumption figures really become more precise?

WLTP should actually reduce the difference between the manufacturer's information and the consumption of real drivers in everyday life.

However, this is not the case in general, because some vehicles use WLTP, measured by both test methods significantly less than with NEDC (e.g. the Mercedes C-Class 180 of the 204 series). Thus, the deviation in everyday life is greater!

If you want to know more precisely, and for your vehicle Deviations between manufacturer information and real consumption we want to find out, we recommend the CarWiki consumption comparison.

There, the manufacturer's information for each motor vehicle was compared in tabular form to an average consumption of real drivers (the data are cumulative values ​​from consumer portals and forums).

Conclusion

The WLTP procedure Since its introduction in 2017, it has met with recognition but also criticism. If you compare some vehicles at CarWiki (a good example are the two series of the Mercedes CLA, because the model 117 came before WLTP and the model 118 after), so you can no clear improvement or reduction of the discrepancies recognized since WLTP.

The transition period for the information in the CoC paper of motor vehicles - WLTP will then finally be established.