Sampling approaches for road vehicle fuel consumption monitoring

EU Regulations introduced in 2019 for light- and heavy- duty vehicles contain provisions requiring the European Commission to set up a mechanism to monitor the real-world representativeness of the fuel consumption determined during the type-approval tests. This study proposes a sampling based approach to collect these data. Two probability-sampling methods (simple random sampling and stratified sampling) and one non-probability sampling method (quota sampling) are discussed. We use data from three user-based datasets (IFPEN, Travelcard and Spritmonitor) and the 2018 European Environment Agency CO2 monitoring dataset. All three user-based datasets provide fairly good representations of their respective countries’ sub-fleets and to a lesser extent the whole fleet. The standard deviation of the fuel consumption gap was consistently found to be approximately 20%. For a population of 15 million vehicles, using simple random sampling, and the standard deviation of the fuel consumption set at 20%, a sample of fewer than 3000 vehicles is required for estimating the average gap with a confidence level of 99% and sampling error less than 1%. Multivariate stratification with three stratification variables (vehicle manufacturer, fuel type and engine rated power) was the optimal combination, reducing the sample size by around 28% compared to simple random sample. Requiring strata specific estimators resulted to an increase of the sample size, as the number of stratification variables increased. Non-sampling errors, such as inaccuracy of On-Board Fuel and/or energy Consumption Monitor (OBFCM) device measurements, are expected to lead to an increase of the required sample size by at least 20%. Samples using quota sampling were taken and had a sampling error less than 3.5%.JRC.C.4 - Sustainable Transpor

Joint Research Centre 2017 light-duty vehicles emissions testing

This report summarises the results of the pilot study on the market surveillance of light-duty vehicles. The emission performance and the CO2 emissions of 15 vehicles are presented. The methodology for vehicle compliance checks defined in the Guidance note published by the European Commission was applied and discussed.JRC.C.4-Sustainable Transpor

Characterisation of real-world CO2 variability and implications for future policy instruments

There is increasing evidence suggesting that real-world fuel consumption and CO2 emissions improvements in the last decade have been much lower than the officially reported ones. Scientific studies show that the offset between officially reported values and real-world vehicle CO2 emissions in Europe has constantly increased over the last years. The difference between officially reported and actual CO2 emissions of vehicles has three main implications: a) it undermines the collective effort to reduce greenhouse gas emissions in Europe, b) it creates an unfair playing field for different competitors, and c) it affects the credibility of vehicle manufacturers. As a fundamental step to deal with this issue the European Commission has replaced the old and outdated NEDC test procedure used so far in the emission type-approval of vehicles by the Worldwide harmonized Light vehicles Test Procedure (WLTP). Being a lab-based test-procedure, the WLTP, by its nature, can only cover part of the CO2 gap. Some stakeholders have suggested that the remaining gap could be tackled by additional measures based on real-world measurements. The objective of the present report is to analyse possible ways to deal with the remaining CO2/fuel consumption gap. In particular, fleet-wide monitoring of real-world fuel consumption and model-based tools able to provide customized information to road users are the measures suggested. In addition, the paper presents experimental evidence on the variability of the CO2/fuel consumption of vehicles, putting into question the idea that a single central estimate of these quantities may be sufficient.JRC.C.4 - Sustainable Transpor

Impact of WLTP introduction on CO2 emissions from M1 and N1 vehicles: Evidence from type-approval and 2018 EEA data

The analysis of official type-approval documents covering the period September 2017 - August 2018 and which were uploaded in the ETAES platform has given a first insight of the impact of the introduction of the WLTP procedure on declared and measured CO2 emissions. The first topic analysed was the ratio between declared WLTP and NEDC emissions. On average, this ratio is higher for diesel ICE vehicles compared to gasoline ICE vehicles. The mean ratio for diesel VH was 1.26 for M1 category and 1.28 for N1 and for VL 1.18 for M1 and 1.22 for N1 category. The 2018 EEA data showed an average ratio of 1.25 for M1 and 1.27 for N1 category. For gasoline ICE vehicles the mean ratio for VH is 1.16 for M1 1.19 for N1 category and for VL 1.13 for M1 and 1.14 for N1 category. The 2018 EEA data show an average ratio of 1.19 for M1 1.16 for N1 category. The highest average ratio for diesel and gasoline VH was calculated for OEM_3 group and for VL for OEM_15 (diesel) and OEM_3 (gasoline) groups. The 2018 EEA registrations data show the highest average ratio coming from OEM_3 (diesel) and OEM_11 (gasoline) groups. For NOVC-HEVs and OVC-HEVs the data sets analysis were much smaller and any conclusions drawn should be treated with caution. The mean WLTP/NEDC ratio for NOVC-HEVs was 1.22 (VH) and 1.18 (VL), which is higher than that of gasoline ICE vehicles. For all OVC-HEVs analysed (weighted-combined CO2 emissions) the ratio for VH is 1.13, but with a range from 0.34 to 1.44 and for VL the average was 1.03 (range: 0.31-1.32). In the 2018 EEA data NOVC-HEVs and OVC-HEVs could not be distinguished. Analysis of Emission type-approval documents (ETA) revealed that for the majority of IP families analysed (70% for VH and 73% for VL) the declared WLTP values were less than 5% higher than the WLTP measured values. In 26% of cases for VH and 23% for VL the over-declaration was between 5% and 10%. In only 4% of cases for VH and 4% for VL OEM’s over-declaration was above 10% (but always below 20%). In total, 18% (266) of IP families are type-approved with only vehicle high (VH), which leads to higher CO2 emissions compared to the interpolation approach. Some OEMs are only type-approving VH (OEM_13, OEM_16, OEM_17, OEM_18, OEM_19, OEM_21, OEM_22, OEM_23, OEM_24, OEM_25, OEM_27, OEM_28), but except OEM_13, the other OEM groups have very low registrations. OEM groups with high registrations (more than half million) and high % of IP families with only VH are: OEM_7 (24%), OEM_5 (22%), OEM_2 (20%), OEM_9 (7%), and OEM_3 (6%). OEM_12 and OEM_10 are another OEMs with high % of IP families with only VH (91% and 73%, respectively) and registrations higher than 200,000. Various inconsistencies and issues have been identified in the data collected. Such inconsistencies should be addressed to ensure correct implementation of the legislation and a level playing field.JRC.C.4-Sustainable Transpor

Risk assessment for the 2024 In-Service Verification (ISV) of CO2 emissions of Light-Duty Vehicles

Article 13 of Regulation (EU) 2019/631 requires the type-approval authorities to verify the CO2 emission and fuel consumption values of light-duty vehicles in-service. Commission Delegated Regulation (EU) 2023/2867 sets out the guiding principles and criteria for defining the procedures for that verification, while Commission Implementing Regulation (EU) 2023/2866 determines the actual verification procedures. Article 3(4) of that Implementing Regulation requires the Commission to set out a methodology for assessing the risk that in-service verification (ISV) families may include vehicles with a deviation in the CO2 emission values and to publish each year a report describing that methodology and listing those families with the highest risk of including such vehicles. JRC has been tasked to perform the risk assessment on behalf of the Commission. When assessing the risk, at least the elements mentioned in Article 3(3) of the Implementing Regulation need to be taken into account, when available. The type-approval authorities must use the Commission’s risk assessment as a basis for selecting the families for their in-service verification. This is the first annual report describing the methodology for the assessment, and the main findings. The risk assessment methodology described is based on a Composite Risk Index (CRI), which combines the probability and severity of a specific occurrence. Probability levels are determined based on the total number of new vehicles from the in-service verification family that have been placed on the Union market. For the severity determination, the data collected pursuant to Article 14 of Implementing Regulation (EU) 2021/392 and through the Commission’s market surveillance test campaigns have been utilized. The real-world data, as referred to in Article 3(3)(e) of Implementing Regulation (EU) 2023/2866, has not yet been used for this risk assessment due to the limited number of such data submitted so far. This report also identifies the ISV families with the highest risk of including vehicles with a deviation in CO2 emissions values. These families are labelled as ISV families with the first testing priority in 2024. Based on the risk assessment, a total of 131 interpolation families, representing 106 ISV families, have been identified as having such high risk. Additionally, a significant number of interpolation families were reported as part of the annual CO2 monitoring for light-duty vehicles, but could not be found amongst those reported to the Commission under Article 14 of Implementing Regulation (EU) 2021/392. Therefore, a number (66) of those missing interpolation families with the highest vehicle registration numbers in the last three years has been selected as high risk, and labelled as ISV families with the first testing priority for the 2024 in-service verification. To further support the vehicle selection for the 2024 in-service verification, this report also presents a random selection of additional IP families both registered and not registered in Database of In-service verification of CO2 Emissions (DICE). Finally, all remaining families that are not registered in DICE are also presented.JRC.C.4 - Sustainable, Smart and Safe Mobilit

From NEDC to WLTP: effect on the type-approval CO2 emissions of light-duty vehicles

The present report summarises the work carried out by the European Commission's Joint Research Centre to estimate the impact of the introduction of the new type approval procedure, the Worldwide Light duty vehicle Test Procedure (WLTP), on the European car fleet CO2 emissions. To this aim, a new method for the calculation of the European light duty vehicle fleet CO2 emissions, combining simulation at individual vehicle level with fleet composition data is adopted. The method builds on the work carried out in the development of CO2MPAS, the tool developed by the Joint Research Centre to allow the implementation of European Regulations 1152 and 1153/2017 (which set the conditions to amend the European CO2 targets for passenger cars and light commercial vehicles due to the introduction of the WLTP in the European vehicle type-approval process). Results show an average WLTP to NEDC CO2 emissions ratio in the range 1.1-1.4 depending on the powertrain and on the NEDC CO2 emissions. In particular the ratio tends to be higher for vehicles with lower NEDC CO2 emissions in all powertrains, the only exception being with the plug-in hybrid electric vehicles (PHEVs). In this case, indeed, the WLTP to NEDC CO2 emissions ratio quickly decreases to values that can be also lower than 1 as the electric range of the vehicle increases.JRC.C.4-Sustainable Transpor

Risk assessment for the 2025 In-Service Verification (ISV) of CO2 emissions of Light-Duty Vehicles

Article 13 of Regulation (EU) 2019/631 requires the type-approval authorities to verify the CO2 emission and fuel consumption values of light-duty vehicles in-service. Commission Delegated Regulation (EU) 2023/2867 sets out the guiding principles and criteria for defining the procedures for that verification, while Commission Implementing Regulation (EU) 2023/2866 determines the actual verification procedures. Article 3(4) of that Implementing Regulation requires the Commission to set out a methodology for assessing the risk that in-service verification (ISV) families may include vehicles with a deviation in the CO2 emission values and to publish each year a report describing that methodology and listing those families with the highest risk of including such vehicles. JRC has been tasked to perform the risk assessment on behalf of the Commission. This is the second annual report describing the methodology for the assessment, and the main findings. The risk assessment methodology described was built upon the approach established in last year’s report, using the concept of the Composite Risk Index (CRI). The CRI combines the probability and severity of a specific occurrence. Probability levels are determined based on the total number of new vehicles from the in-service verification family that have been placed on the Union market. For the severity determination, the data collected pursuant to Article 14 of Implementing Regulation (EU) 2021/392 and the real-world data, as referred to in Article 3(3)(e) of Implementing Regulation (EU) 2023/2866 have been used. In addition, tests performed through the Commission’s market surveillance test campaigns and from the in-service conformity tests pursuant to Regulation (EU) 2017/1151 have been part of this year’s risk assessment. This report identifies the ISV families with the highest risk of including vehicles with a deviation in CO2 emissions values. Based on the risk assessment and random selection, 333 unique interpolation families, representing 250 unique ISV families, have been identified as having such high risk. Additionally, some interpolation families were reported as part of the annual CO2 monitoring for light-duty vehicles, but could not be found amongst those reported to the Commission under Article 14 of Implementing Regulation (EU) 2021/392. As a result, a number (24) of those missing interpolation families with the highest vehicle registration numbers in the last three years and manufacturers with the highest percentage of missing families, has been selected and included in the list of high risk families for the 2025 in-service verification. In addition, and to fill the gap between the 2025 ISV testing needs and to cover all manufacturers, the final list of families includes also 13 interpolation families selected based on medium risk or the highest registration volumes. In total, the ISV 2025 testing plan comprises 370 unique interpolation families. To further support the vehicle selection for the 2025 in-service verification, this report also links potential risks associated with ISV families flagged as high risk to chassis-dynamometer testing, road load tests, or the implementation of artificial strategies. Consequently, each of the listed ISV families was marked for specific types of tests based on the outcomes of this risk assessment.JRC.C.4 - Sustainable, Smart and Safe Mobilit

On-road vehicle emissions beyond RDE conditions

Passenger cars are an important source of air pollution, especially in urban areas. Recently, real-driving emissions (RDE) test procedures have been introduced in the EU aiming to evaluate nitrogen oxides (NOx) and particulate number (PN) emissions from passenger cars during on-road operation. Although RDE accounts for a large variety of real-world driving, it excludes certain driving situations by setting boundary conditions (e.g., in relation to altitude, temperature or dynamic driving). The present work investigates the on-road emissions of NOx, NO2, CO, particle number (PN) and CO2 from a fleet of nineteen Euro 6b, 6c and 6d-TEMP vehicles, including diesel, gasoline (GDI and PFI) and compressed natural gas (CNG) vehicles. The vehicles were tested under different on-road driving conditions outside boundaries. These included ‘baseline’ tests, but also testing conditions beyond the RDE boundary conditions to investigate the performance of the emissions control devices in demanding situations. Consistently, low average emission rates of PN and CO were measured from all diesel vehicles tested under most conditions. Moreover, the tested Euro 6d-TEMP and Euro 6c diesel vehicles met the NOx emission limits applicable to Euro 6d-TEMP diesel vehicles during RDE tests (168 mg/km). The Euro 6b GDI vehicle equipped with a gasoline particulate filter (GPF) presented PN emissions < 6×1011 #/km. These results, in contrast with previous on-road measurements from earlier Euro 6 vehicles, indicate more efficient emission control technologies are currently being used in diesel and gasoline vehicles. However, the results described in this report also raise some new concerns. In particular, the emissions of CO (measured during the regulated RDE test, but without an emission limit associated to it) or PN from PFI vehicles (presently not covered by the Euro 6 standard) showed elevated results in some occasions. Emissions of CO were up to 7.5 times higher when the more dynamic tests were conducted and the highest PN emissions were measured from a PFI gasoline vehicle during dynamic driving. The work also investigates how NOx, CO, PN and CO2 on-road emissions from three vehicles are impacted by sub-zero ambient temperatures and high altitudes. Two of the tested vehicles were Euro 6d-TEMP certified vehicles, one diesel and one gasoline, and one was a Euro 6b plug-in hybrid vehicle. The vehicles were studied during tests that do not fulfil the boundary conditions in terms of maximum altitude, altitude gain, and/or minimum temperature. The obtained emissions were compared to those obtained during tests performed along RDE routes. The results indicate that cold ambient temperature and high altitude, outside the RDE boundary conditions, lead to in higher NOx, CO and PN emissions compared to moderate conditions of temperature and altitude. Nonetheless, the two Euro 6d-TEMP vehicles tested in those extreme conditions yielded NOx emissions factors that fulfilled the Euro 6d-TEMP emission requirements. Our work underlines the importance of a technology- and fuel-neutral approach to vehicle emission standards, whereby all vehicles must comply with the same emission limits for all pollutants.JRC.C.4-Sustainable Transpor

Joint Research Centre 2019 Light-Duty Vehicles emissions testing

This report summarises the results of the 2019 pilot study on the market surveillance of light-duty motor vehicles tailpipe emissions. Environmental pollutant emissions performances and CO2 emissions of thirty-five light-duty vehicles are presented. A new methodology for Euro 6d-TEMP and Euro 6d vehicle compliance checks is presented, applied and discussed.JRC.C.4 - Sustainable Transpor

Environmental Impact Assessment of the Nuclear Reactor in Vinca, Based on the Data on Emission of Radioactivity from the Literature - a Modeling Approach

Research activities of Vinca Institite have been based on two heavy water research reactors: a 10 MW one, RA, and zero power, RB. Reactor RA was operational from 1962 to 1982. In 2010, spent fuel has been sent to the country of origin, and the reactor now is in decommissioning. During the operational phase of the reactor there were no recorded accidental releases into the environment, only operational ones. Results of the environmental impact assessment of the assumed emission of radionuclides from the ventilation of nuclear reactor RA in Vinca to the atmospheric boundary layer are presented in this paper. Evaluation was done by using the Gaussian straight-line diffusion model and taking into account characteristics of the reactor ventilation system, the assumed emission release of radioactivity (from the literature), site-specific meteorological data for six-year period and local topography around nuclear reactor, and corresponding dose factors for inventory of radionuclides. Based on the described approach, and assuming that the range of appropriate meteorological data for six year period for the application of described mathematical model is enough for this kind of analysis, it can be concluded that the nuclear reactor RA, in the course of its work from 1962 to 1982, had no influence on the surrounding environment through the air above regulatory limits