Volkswagen emissions scandal and vehicle type approval Contents

4Emissions tests

Euro emissions standards

55.The EU periodically reduces the legal limits on emissions through the introduction of new ‘Euro’ emissions standards. Euro standards were introduced in 1992 to reduce pollutants from vehicles and have been a successful mechanism for improving air quality, leading to reductions in NOx, particulates and hydrocarbon emissions.114 The official Euro 6 NOx limit is over 90% lower than the first Euro standard introduced in 1992. Real-world test data from Emissions Analytics indicated NOx emissions from the latest Euro 6 diesel cars had been reduced by 49% relative to Euro 5 cars.115 Meeting NO2 limits close to busy roads continues to be a challenge. In some areas transport is responsible for 80% of roadside NOx on average.116

UK National emissions of air pollutants117

The emissions gap

56.The Government found that air quality had not improved at the expected rate despite reductions in the official emissions limits. The Department for Environment, Food and Rural Affairs commissioned a report in 2013 that found that NOx emissions from diesel cars peaked around the year 2000 but there has been little change since.118 One reason for that is the NEDC’s failure to keep pace with vehicle technology and real-world driving conditions. Dr James Tate, Institute for Transport Studies, Leeds University, said “It is quite surprising how there can be a test that is so unrepresentative of real-world driving.”119 That has led to a substantial ‘emissions gap’ where vehicles in the real-world emit considerably more NOx than they do when tested in the laboratory. Nick Molden, Chief Executive Officer, Emissions Analytics, explained the scale of the emissions gap for NOx and CO2:

On average, across 400 vehicles tested, NOx emissions are four times the regulated level, at around 300 mg/km for Euro 6 in real-world driving.

[ … ] CO2 emissions are on average 31% above the official level, across 700 vehicles tested, which implies that fuel economy (MPG) is 24% lower than customers are being led to expect.120

Real-world emissions are not currently regulated so those excesses are not illegal although they are misleading for consumers, regulators and for Governments that need to model pollution levels accurately.

57.Emissions Analytics said that the principal reasons for the disparity were threefold:

i)The New European Driving Cycle has a much gentler driving profile than real-world driving and tends to generate better fuel economy and lower emissions;

ii)The loopholes in the test protocol, particularly around the coast-down test and other tolerances, mean that an official dynamometer-based NEDC test may get a better result than the same NEDC cycle on the real road;

iii)As the overlap in engine load characteristics between the NEDC and real-world driving is relatively limited, the engine calibration can be set to meet NOx limits when officially tested but with better fuel economy (and likely higher NOx emissions) in real-world driving.121

Flexibilities in the test procedure were the result of how the EU framework Regulation was drafted. Greg Archer, Clean Vehicles Manager, Transport & Environment, said “that framework was drafted in a way that simply was not rigorous enough. It said things like the type-approval authority—the people who check that the car is legal—’may’ do this and ‘could’ do that”.122 That enabled manufacturers to engineer cars specifically to pass the narrow parameters of the NEDC without regard for how cars performed in the real world.

58.Manufacturers are able to submit cars to undergo the NEDC that have been optimised to perform well in test conditions. Greg Archer said the industry called such cars ‘golden vehicles’ although the use of that term was rejected by figures from within the motor industry.123 Greg Archer said there were approximately 20 different ways that manufacturers optimised test cars. Mike Hawes, Chief Executive, Society of Motor Manufacturers & Traders (SMMT), said that he had not heard of some of the more substantial optimisations that manufacturers are alleged to have employed.124 Tony Soper, Technical Specialist for Homologation, Millbrook, said that some permissible optimisations were to “the letter of the regulation, not necessarily the spirit”.125 Those included charging the battery so there was less parasitic loss from the engine and using high pressure tyres which reduced frictional losses.126 He said:

To give you an example, it may be prepared such that the oil level is at the lower end, at the bottom of the dipstick rather than at the top of the dipstick. That is perfectly acceptable within the emissions regulations, and it will result in a small advantage in frictional losses. Those are the sorts of special preparations that have been made in the past to such vehicles.127

Dr George Gillespie, Chief Executive Officer, Horiba Mira, said that “Because of the vagaries of testing there are plus and minus limits on various parameters. Yes, you could have a vehicle tested at one end and you could buy a vehicle at the other end.”128

59.Witnesses pointed out that the extent to which test vehicles could differ from vehicles on sale was restricted by the ‘Conformity of Production’ system.129 Conformity of Production is the means of demonstrating the ability to mass produce a vehicle according to the specification certificated in type-approval documentation. It is mandatory that manufacturers have a Conformity of Production system in place before type approval is granted. A Conformity of Production assessment takes place at a manufacturing facility which has the appropriate equipment, testing environment and quality processes to ensure test vehicles are representative of the final manufactured vehicles.130 Technical services conduct conformity of production testing on a regular basis for manufacturers, “where a random vehicle is selected from the end of the production line and brought to [its facilities] to be tested.”131

EU reforms

60.The Commission had known of the emissions gap since at least 2011.132 The motor industry itself recognises the need to replace the NEDC.133 New test rules will take time to formulate but by any standard the rate of progress has been slow. It has taken the VW emissions scandal before any meaningful action to begin.134 The Commission is now legislating for a real-world test to complement laboratory testing called a Real Driving Emissions (RDE) test. RDE will ensure that NOx measured during the laboratory test is confirmed in real-world conditions. Test cars will be driven on a road according to random acceleration and deceleration patterns. Emissions will be measured by Portable Emission Measuring Systems (PEMS) installed within the car. RDE testing will reduce the difference between emissions measured in the laboratory and those measured on the road. It will reduce the risk of cheating with defeat devices.135

61.RDE testing will be introduced through four packages, the first and second of which have been agreed by member states and the European Parliament. The first RDE package introduced the concept of RDE procedures with PEMS. The use of PEMS applied from 1 January 2016 and national motoring authorities should now be using RDE for monitoring purposes. EU rules require the manufacturer and the approval authority to provide RDE test results to any interested party but the Commission plans to propose relevant legislation making that information publicly available, possibly through a database, without the need to contact manufacturers.136 The second RDE package provided for additional margins for emissions under RDE and the dates for their implementation. The third RDE package will address PEMS testing for particle numbers, the inclusion of the cold start137 and after-treatment system regenerations in the RDE test, special provisions for RDE hybrid testing and the inclusion of the Conformity Factors in the Certificate of Conformity. The text is due to be voted at the Technical Committee on Motor Vehicles (TCMV) in the fourth quarter of 2016. The fourth RDE package will include measures for in-service surveillance testing by independent parties such as other approval authorities not involved in the initial type approval or by NGOs. Its preparation will begin in September 2016 and the TCMV should vote on it in the first half of 2017.138

62.The current Euro 6 legal NOx limit is 80mg/km. The Commission has introduced not-to-exceed (NTE) NOx limits above the existing Euro 6 limit under the second RDE package to take account of variabilities that arise from testing with on-board PEMS equipment. The NTE limit is the legal NOx limit plus a margin called the ‘conformity factor’. The Commission is introducing a temporary higher conformity factor before introducing a lower conformity factor a few years later. This means:

i)car manufacturers will have to bring down the discrepancy between lab and real world tests to a conformity factor of a maximum 2.1 (110%) for new models by September 2017 (for new vehicles by September 2019);

ii)this discrepancy will be brought down to a factor of 1.5 (50%), taking account of technical margins of error, by January 2020 for all new models (by January 2021 for all new vehicles)

Nick Molden, Chief Executive, Emissions Analytics, said a 2.1 conformity factor is “much greater than the inherent variability in PEMS testing”. He said a more realistic conformity factor would be about 1.2 to 1.3.139 The Commission itself originally proposed setting the temporary and final conformity factors at 1.6 and 1.2 respectively. That would have resulted in NTE NOx limits in real-world conditions of 128mg/km followed by 96mg/km but the agreed limits are substantially less stringent than that—168mg/km and 120mg/km. The agreed NTE limits resulted in rules that effectively raised official emissions limits for the first time. In practice, cars are exceeding official limits by 400% on average, so the new limits should result in a real-world NOx reduction.

63.Critics of the conformity factors argued that the proposals should have been rejected on the grounds that they are illegal under the EU’s own legislation. It was argued that the size of the proposed conformity factors had been made for political reasons—to protect the interests of Europe’s motor industry—and not for reasons based upon scientific evidence. Transport & Environment said, “the Commission and member states’ decision exceeds the powers of implementing legislation and is therefore illegal. Implementing legislation can only take uncertainty in the testing procedure into account when revising limits”. ClientEarth, an environmental advocacy group, said:

The European Parliament has the power to oppose the implementing measures adopted by the Commission, if they exceed the implementing powers granted by the EU legislature or are not compatible with the aim or the content of the Euro 6 Regulation.

In setting the temporary and final conformity factors applicable to RDE tests, the Commission has taken a political decision to favour the commercial interests of car manufacturers over the protection of the health of European citizens. This decision therefore exceeds the implementing powers granted by the EU legislature and is incompatible with the Euro 6 Regulation’s aim to progressively reduce vehicle emissions and achieve air quality objectives.

The decision is therefore illegal and should be vetoed by the European Parliament.140

The Commission said the proposed conformity factors were set on the basis of an in-depth analysis of several ‘error sources’ that arise from the use of PEMS. “The analysis provides a range of [conformity factors], which are considered to be compliant with the legal requirements set by Regulation (EC) 715/2007. The [conformity factors] voted by the TCMV141 are within this range.”142 Ian Yarnold, Head of the International Vehicle Standards Division, DfT, said the Government agreed with the conformity factors and that their basis was a “judgement call” based on “DEFRA’s modelling about where we are, where they need to be for the ambient air quality issues and how quickly we felt we could get there.”143

64.There was a great deal of criticism about the extent to which motor manufacturers were able to shape the Commission’s proposals for RDE tests. The Corporate Europe Observatory, an advocacy group, used EU Freedom of Information rules to publish communications between ACEA, a car industry trade association, and the Commission. ACEA made a number of requests of the Commission, some of which were accepted, partially accepted or rejected.144 ACEA successfully lobbied for the removal of ‘cold-starts’ from the recent RDE packages.145 ‘Cold starts’ refers to measuring emissions that occur during starting and warming up a car when the engine is cool which typically results in high emissions. Removing cold-starts from the test made it much less representative of real-world driving. As noted above the Commission has now said that it still intends to develop a plan to measure cold starts in future addendums to the regulation.146

65.The Commission has committed to an annual revision clause to examine the case for reducing the final conformity factor. The aim is to bring the conformity factor down to 1 as soon as possible and at the latest by 2023.147 Reductions should reflect decreasing measurement uncertainties from the PEMS based on increased experience and improvements over time due as a result of technical progress.148 The Commission only has the power to propose a reduction in the conformity factor. Any reduction would still need to be agreed upon by member states.149 There is no certainty that member states would be more receptive to new evidence presented by the Commission than they were to the evidence presented in advance of the conformity factors that were agreed previously.

66.The agreed conformity factors are a step in the right direction. Remaining RDE test measures are still to be agreed but once RDE testing is implemented it should result in lower real-world NOx emissions. We were disappointed that the Department for Transport did not strive for stricter conformity factors given scientific evidence that shows NOx could have been cut much faster. We call on the Department to influence negotiations in favour of a conformity factor of 1.2 or 1.3 at the next available opportunity and to bring the conformity factor down to 1 as soon as possible.

World-wide Light-vehicle Test Procedures

67.The Commission is introducing a new test procedure known as the Worldwide Light-vehicle Test Procedures (WLTP) which will be used to measure CO2 emissions and fuel economy. The development of the WLTP began at the United Nations in 2007. The UN aimed to develop a testing regime that better reflected actual driving conditions and was harmonised globally to make it easier and cheaper for manufacturers to offer the same models in different markets without the need for separate type approvals. This should represent a significant cost saving to manufacturers which should, in large part, be passed on to consumers. The Government has been right to encourage and shape the implementation of the WLTP. The Commission anticipates that the WLTP will be mandatory for new vehicle models from September 2017.

68.There is a substantial gap between CO2 emissions detected under the NEDC and those detected in the real world which the WLTP will help to reduce. Greg Archer from Transport & Environment said:

the problem has been getting worse and worse year on year. We have seen the gap between the test results and the real world performance of the vehicles increasing. Going back to 2000, the gap was just 8% on average; in 2014, it was 40% on average.150

The WLTP is conducted in a laboratory but the test parameters are stricter and are a better reflection of real-world driving conditions when compared to the NEDC. Horiba Mira said that it is important that the WLTP is not seen as “a test to fully answer and offer solutions to the discontent and questions raised by consumers. To develop a testing regime which fully reflects all driving styles, road conditions and vehicle technology and at the same time offers a robust and repeatable test is unfeasible.”151 Emissions Analytics challenged the idea that CO2 emissions could not also be measured in real-world conditions:

On the CO2 side, the same on-road element is not being introduced in the test. There is a very strong argument that it should be. Nevertheless, [ … ] In our calculations, it will reduce that gap of about 31% today down to about 15%.152

Greg Archer also said that real world CO2 testing was needed despite acknowledging that the WLTP was a step in the right direction.153

69.We welcome the Department’s efforts to implement the Worldwide Light-vehicle Test Procedure. We recognise that global test and certification standards bring savings to vehicle design and development which should in theory reduce prices for consumers. We recommend that the Department assess the viability of introducing a real-world element to CO2 testing.


70.The transition to WLTP requires a number of important issues to be addressed including the impact that the WLTP will have on Vehicle Excise Duty (VED) bands. According to the SMMT VED bands will need to be updated to avoid market distortion.154 That is because VED is based on car engine size, official CO2 emissions and the date of first registration. A car’s official CO2 emissions are likely to be higher when tested under the WLTP than when tested under the NEDC which will affect which VED band applies. The DfT said that once WLTP had been implemented “decisions will be taken about VED bands”.155

71.The SMMT also said that there will need to be a significant lead time to accommodate the changes that manufacturers and the DfT will have to make to databases so that cars approved on WLTP can be registered by the DVLA. The SMMT said that discussions have begun on how to transition from NEDC to WLTP.156

Car labelling

72.In addition, the SMMT said that discussions have begun with the Commission about how to transition from the NEDC to the WLTP for consumer labelling purposes.157 The introduction of the stricter WLTP will make it difficult for consumers to compare vehicle performance between newer and older models. The Commission launched an evaluation of the Car Labelling Directive in 2015 to examine its implementation and achievements compared to what was expected. The Car Labelling Directive158 aimed to raise consumer awareness on the fuel use and CO2 emission of new passenger cars so that consumers could be incentivised to purchase or lease cars which used less fuel and emit less CO2. The evaluation is expected to be concluded in July 2016 with the publication of a Commission Staff Working Document that will summarise the main findings of the evaluation and identify any potential follow-up work. Before the end of 2016, independently of the evaluation results, the Commission said that it might provide guidance on how to address the introduction of the WLTP in the context of the Car Labelling Directive.159 Graham Hope, Editor, Auto Express and Carbuyer, said the US car labelling standards were a useful model that could be used in Europe: “There is a much more transparent labelling system over there, and the average mpg is displayed very prominently. There is an average fuel cost and also a figure displayed that shows how much more or less you would spend on fuel over five years compared with the average car.”160

73.The transition to WLTP will have a number of consequences which must be addressed carefully if they are not to lead to confusion amongst consumers. In particular the Department for Transport and HM Treasury need to assess the impact that the introduction of the WLTP will have on cars’ CO2 emissions and the related VED bands. That information must be provided to motorists as soon as possible and we call upon the Government to publish that information. Motorists must not be financially penalised as a result of an improved testing and certification regime. The Department for Transport should consider publishing information on to explain how vehicles tested under WLTP compare with those tested under the NEDC by including a ‘conversion factor’ allowing motorists to compare emissions standards and performance.

74.The Department for Transport should examine ways of standardising and optimising the format of vehicle labelling to ensure consumers are provided with information that is intuitive and user-friendly allowing for simple and accurate comparisons between cars. The DfT must take examples of best practice from other jurisdictions. During the period of transition to the WLTP and RDE car labelling will require additional information so that consumers can compare standards on a like for like basis between newer and older vehicles.

Emission Testing Programme

75.On 10 November 2015 the Secretary of State announced a Vehicle Emissions Testing Programme (ETP) to look for the use of defeat devices by other manufacturers and to improve its understanding of the real-world emissions performance of diesel vehicles in the UK. The DfT funded the programme to ensure the testing would be seen as independent and neither the cars nor the testing facilities were provided by the vehicle industry, although tests on VCA type approved Škoda vehicles was paid for by Škoda.161 The Secretary of State said the programme was conducted in collaboration with France and Germany to reduce duplication of effort and to generate savings.162 The ETP had an initial budget of £650,000 but that rose to approximately £1,000,000 as of April 2016.163

76.The ETP did not detect evidence that any other manufacturer had used the same test cycle manipulation strategy as VW. Nevertheless all the vehicles that were tested emitted higher NOx levels in real-world driving conditions compared to the laboratory with results varying between different makes and models. The following graph shows the real-world emissions performance for a range of Euro 5 diesel cars. The black dotted line represents the Euro 5 legal NOx limit (180mg/km). The red line represents the average NOx emissions for all vehicles. The vehicles that performed worst were about ten times the legal limit. The best performing vehicle was still three times the legal limit.

Real driving NOx emissions – Euro 5 vehicles (note: direct comparisons should not be made between vehicles as test conditions varied)164

77.The ETP found one reason for the discrepancy between laboratory and real-world emissions was related to how manufacturers used Exhaust Gas Recirculation (EGR) strategies—a system used to reduce NOx emissions from vehicles. Manufacturers used temperature dependent strategies to regulate the amount of EGR that was used. Some EGR systems were programmed to stop operating, or switch to a less powerful mode, at temperatures just below those specified for the NEDC but are normal ambient temperatures in European countries.165 The result was lower NOx emissions in the laboratory than on the road. The EU’s prohibition on defeat devices covers any element or design that senses temperature and “reduces the effectiveness of the emission control system under conditions which may reasonably be expected to be encountered in normal vehicle operation and use”. Recognising temperature to restrict the emissions control strategy is exactly what many manufacturers have been doing. Manufacturers told the DfT that it was necessary to make the EGR system less effective at lower temperatures to protect the engine from damage, which constitutes a legal exemption from the defeat device prohibition. While those EGR strategies might be interpreted as legal, some manufacturers are using them to exploit loopholes in the NEDC and Framework Regulation; they are a defeat device by another name. The DfT has not published any record of its discussions with manufacturers on their reasoning on the necessity of their temperature-dependent EGR strategies but appears to be accepting that reasoning at face value. The DfT wrote to the Commission to draw its attention to manufacturers’ practices and called for regulations “to be updated quickly to ensure there is complete transparency in how these systems operate and their effect on emissions in different conditions (such as temperature).”166

78.The Commission’s reforms to type approval have left the wording of the prohibition on defeat devices unchanged. The Commission said, “The current definition of defeat devices in the European legislation is adequate.” Manufacturers will be required to declare their emission strategies to approval authorities in the future and the Commission believes that will help to identify emission strategies that are not permitted, although it did not rule out revisiting definitions in the future.167 The DfT said that it did “not believe the EU’s definition of a defeat device is too narrow” and it supported the introduction of requirements to disclose alternative emissions strategies.168 The ICCT highlighted differences that remain between the stricter US reporting requirements for emission control strategies and those that will be implemented in Europe. The obligation for manufacturers to disclose emission control strategies in both jurisdictions will be similar but in Europe the regulation “does not give unequivocal guidance to Member States concerning the technical evaluation of the provided information; it does not enumerate criteria that should be used to approve or reject claimed exceptions to the defeat device prohibition; and it does not indicate how to determine which components are part of the emission control system.”169

79.We disagree with the European Commission and the Department for Transport on the contention that the regulations for prohibiting defeat devices is adequate. It has led to an unacceptable dispute over the legality of VW’s actions in Europe as well as the emissions control strategies of a wide-range of other manufacturers; we believe some of those strategies are defeat devices by another name. We welcome the DfT’s support for plans to introduce requirements for manufacturers to disclose their emissions control strategies which will go some way to reduce the flaws in the prohibition but we have not seen evidence that the European Commission’s plans go far enough. We recommend that the DfT work with the Commission to ensure that the prohibition on defeat devices is strengthened with guidance for approval authorities on how to evaluate claims that emissions control strategies constitute a viable exemption to the prohibitions on defeat devices, introduce a consistent, method to approve or reject claims for exemptions and to introduce a requirement on manufacturers to prove to approval authorities that alternative emission control strategies are necessary and that no viable alternative exists.

80.The ETP report published high-level results only. The DfT committed to publishing the underpinning data available in a format that was intelligible for the public at the earliest opportunity on The DfT had hoped it would be able to publish that information in May 2016 but that did not happen. The DfT said that it possesses a further data set that shows “second-by-second emissions readings for all of the vehicles during the testing.” They said that it was impractical to publish those files on because of their size. Those files would be made available on request using an external storage device such as a memory stick or a CD instead.170

81.We welcome the Department for Transport’s Vehicle Emissions Testing Programme report. We were disappointed that the DfT did not publish the underpinning data in May 2016. The DfT must make all the underpinning data it holds available for independent scrutiny at the earliest opportunity. The DfT must ensure that the larger data sets are easy to request and the mechanism for doing so is well signposted on The DfT must publish records of its discussions with manufacturers on their temperature-dependent EGR strategies including the reasons provided by each manufacturer for high emissions in ambient temperatures with reference to the manufacturers’ descriptions of the influence of temperature on the emission control strategy and the temperature below which the EGR is switched off or reduced for each vehicle.

114 Department for Transport (VTA008) para 23

116 Department for Transport, Vehicle Emissions Testing Programme, April 2016, para 2.2

117 Department for Transport, Vehicle Emissions Testing Programme, April 2016, para 2.2

119 Vehicle type approval, Q2

120 Emissions Analytics (VTA0009)

121 Emissions Analytics (VTA0009)

122 Vehicle type approval, Q9

123 Vehicle type approval, Qq135–140

124 Vehicle type approval, Qq 39–42

125 Vehicle type approval, Q150

126 Vehicle type approval, Qq145 & 146

127 Vehicle type approval, Qq139–140

128 Vehicle type approval, Q164

130 Horiba Mira (VTA0028) page 2

133 SMMT (VTA0011) para 22

137 See paragraph 63

140 Client Earth, Legality of the Conformity Factors in the RDE tests, December 2015, p3

141 Technical Committee on Motor Vehicles (TCMV) is comprised of officials from EU Member States

143 Vehicle type approval, Qq560 & 561

145 New York Times, VW argued for easing new EU tests on emissions, 1 December 2015

146 See para 60

149 Vehicle type approval, Q309

150 Vehicle type approval, Q7

151 Horiba Mira (VTA0028) page 4

152 Vehicle type approval, Q35

153 Vehicle type approval, Q36

154 SMMT (VTA0011) para 28

156 SMMT (VTA0011) para 29

157 SMMT (VTA0011) para 29

160 Vehicle type approval, Q88

163 Vehicle type approval, Q476

164 Department for Transport, Vehicle Emissions Testing Programme, April 2016, para 5.21

165 Transport & Environment have said the average ambient temperature is 9 degrees centigrade

169 ICCT (VTA0023) page 16

© Parliamentary copyright 2015

12 July 2016