NEDC (New European Driving Cycle)

It has been the European driving cycle used so far for the measurement of fuel consumption and emissions from passenger cars and light commercial vehicles. The first European driving cycle came into force in 1970 and referred to an urban route. In 1992 it was also considered to have an extra-urban phase and since 1997 it has been used for measuring consumption and CO2 emissions. However, the composition of this cycle is no longer consistent with current driving styles and distances travelled on different types of roads. The average speed of the NEDC is only 34 km/h, accelerations are low and the maximum speed is just 120 km/h.


WLTP procedure

WLTP uses new Worldwide harmonised Light-duty vehicle Test Cycles (WLTC) to measure fuel consumption, CO2 and pollutant emissions from passenger cars and light commercial vehicles. The new protocol aims to provide customers with more realistic data, better reflecting the daily use of the vehicle. The new WLTP procedure is characterized by a more dynamic driving profile with more significant acceleration. The maximum speed increases from 120 to 131.3 km/h, the average speed is 46.5 km/h and the total cycle time is 30 minutes, 10 minutes more than the previous NEDC. The distance travelled doubles from 11 to 23.25 kilometers. The WLTP test consists of four parts depending on the maximum speed: Low (up to 56.5 km/h), Medium (up to 76.6 km/h), High (up to 97.4 km/h), Extra-high (up to 131.3 km/h). These parts of the cycle simulate urban and suburban driving and driving on extra-urban roads and motorways. The procedure also takes into account all vehicles’ optional contents that affect aerodynamics, rolling resistance and vehicle mass, resulting in a CO2 value that reflects the characteristics of the single vehicle.

Comparison: NEDC vs. WLTP

Cycle time
20 minutes
30 minutes
11 km
23.25 km
Maximum speed
120 km/h
131.3 km/h
Average speed
34 km/h
46.5 km/h
Driving phases
2 phases
4 more dynamic phases
Influence of optional equipment
Not considered
Additional features (which can differ per car) are taken into account
Gear shifts
Fixed gear shift points
Different gear shift points for each vehicle
Stop time

The transition from NEDC to WLTP

The WLTP procedure will gradually replace the NEDC procedure. For passenger cars and light commercial vehicles of Class I, the new WLTP procedure applies to new type-approved models from 1 September 2017 and to all registrations from 1 September 2018, and is mandatory for all EU Member States. For light commercial vehicles of Class II and III the new procedure applies to new type-approved models from 1 September 2018 and to all registrations from 1 September 2019.

Until the end of 2020, both fuel consumption and CO2 emission values in WLTP and NEDC will be present in the vehicle documents. Indeed, NEDC values will be used to assess the average emissions of cars and light commercial vehicles registered in the EU throughout 2020. In addition, some countries may continue to use the NEDC data for fiscal purposes. From 2021 onwards, WLTP data will be the only consumption/ CO2 emission values for all vehicles. Used vehicles will not be affected by this step and will maintain their certified NEDC values.

Road consumption and emissions of passenger cars and light commercial vehicles

The new WLTP test procedure is more representative of current driving conditions than the NEDC procedure, but it cannot take into account all possible cases including the effect of the driving style that is specific to each individual driver. Therefore, there will still be a difference between emissions and consumption measured in the laboratory and those resulting from the use of the vehicle in the real world, and the extent of this difference will depend on factors such as driving behavior, the use of on-board systems (e. g. air conditioning), traffic and weather conditions that are characteristic of each geographical area and each driver. For this reason, only a standardized laboratory test allows to obtain values with which it is possible to compare vehicles and different models in a fair way.

RDE (Real Driving Emissions)

a test focused on verifying emissions on the road

The RDE test verifies that vehicles maintain low emissions even under real road driving conditions. The RDE test does not replace but complements the WLTP laboratory test. During the RDE test, the vehicle is driven on the road in a wide range of different conditions. Conditions include different altitudes and temperatures, additional payload, uphill and downhill driving, urban roads (low speed), rural roads (average speed), highways (high speed).

In order to measure pollutant emissions while driving the vehicle on the road, test cars are equipped with portable measurement systems (PEMS) that provide full real-time monitoring of the main pollutants emitted by the vehicle. PEMS are complex devices that integrate advanced gas analyzers, exhaust gas mass flow meters, weather station, satellite-based geolocation and a network connection. The data collected is analyzed to verify that the boundary conditions of the RDE journey have been met and that emissions are within the limits of the regulation. The limits not to be exceeded are defined as those prescribed in the laboratory test (WLTP) multiplied by compliance factors. Compliance factors shall take into account the margin of error of the instrumentation that does not measure at the same level of accuracy and repeatability as that used in the laboratory test. The RDE test for passenger cars and light commercial vehicles of Class I applies to new type-approved models from 1 September 2017 and to all registrations from 1 September 2019 in case of nitrogen oxides (NOx) verification, with a compliance factor of 2.1. However, in the case of particle number (PN) verification, the compliance factor is 1.5 and applies to all registrations from 1 September 2018. For light commercial vehicles of Class II and III, the RDE test applies one year later.

What changes for customers

The new WLTP procedure will provide a more realistic criterion for comparing the fuel consumption and           CO2 emission values of different vehicle models as it has been designed to better reflect real driving behavior and take into account the specific technical characteristics of the individual model and version, including optional equipment. To ensure clarity and maximum possible transparency, FCA will provide retailers and customers with detailed information on the fuel consumption and CO2 emission values of each configured car and on the minimum and maximum extremes of the various models.