New Emissions Testing: What You Need To Know About WLTP

Introducing the WLTP

When you choose an Infiniti car, we want you to have all the facts at your disposal. This includes having accurate and clearly expressed information about vehicle emissions and fuel consumption. New legislation is now in place to make this easier. This is called the Worldwide Harmonised Light Vehicles Test Procedure - or WLTP for short.

All manufacturers will have to have their cars tested using the WLTP, before they can be put on sale. Implementation began in September 2017 for new models or new powertrains, and WLTP is progressively replacing the previous testing process, the New European Driving Cycle or NEDC. During the transition from NEDC to WLTP, sometimes results using both systems will be quoted.

WLTP - a better way of testing

The WLTP testing method gives a more realistic set of figures for emissions and fuel consumption than the NEDC - closer to what you could achieve in everyday driving. For example, the new test is conducted within a wider range of temperatures, lasts longer and covers more than double the NEDC test driving distance.

To better reflect normal driving conditions, the new test cycle includes more severe acceleration, shorter stops, a higher average speed and a higher maximum speed. Instead of combining simulated urban and extra urban driving, the vehicle is now tested in four different speed ranges. The readings obtained thus reflect different driving styles in different conditions. The figures also take into account differences in a vehicle's equipment - including individual options - across the model range in question.

On road figures

Despite its greater rigour, the WLTP remains purely a laboratory process. In order to make the final figures even more representative, a second testing procedure is being introduced. This is called the Real Driving Emissions test - RDE for short. This requires vehicles to be tested on the road, in conditions that more accurately represent what an average driver could reasonably expect to achieve.

The RDE test combines uphill and downhill driving with low speed urban roads, medium speed rural roads and high speed motorway mileage, and takes in high and low altitudes and variations in vehicle load and external temperature.

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