EU: Cars and Light Trucks

Background

European Union emission regulations for new light duty vehicles—including passenger cars and light commercial vehicles (LCV)—were once specified in Directive 70/220/EEC with a number of amendments adopted through 2004. In 2007, this Directive was repealed and replaced by the Euro 5/6 Regulation and, in 2024, the Euro 7 Regulation. Some of the important regulatory steps were:

• Euro 1 standards (also known as EC 93): Directives 91/441/EEC (passenger cars only) or 93/59/EEC (passenger cars and light trucks)
• Euro 2 standards (EC 96): Directives 94/12/EC or 96/69/EC
• Euro 3/4 standards (2000/2005): Directive 98/69/EC, further amendments in 2002/80/EC
• Euro 5/6 standards (2009/2014): Regulation 715/2007 (“political” legislation) [2899] and several comitology regulations
  • Regulation 692/2008—the main implementing legislation [2764][2900]
  • Regulation 459/2012—PN limits for gasoline vehicles and final Euro 6 OBD [2898]
  • Regulation 630/2012—provisions for hydrogen, hydrogen/natural gas (H2NG) and hybrid and eclectic vehicles [2901]
  • Real Driving Emissions (RDE): Regulation 2016/427 [3362], Regulation 2016/646 [3638], Regulation 2017/1154 [3637][3819], Regulation 2018/1832 [5137][5138]
  • WLTP/WLTC testing: Regulation 2017/1151 [3635][3818], Regulation 2017/1347 [3636]
• Euro 7 standards (2026): Regulation 2024/1257 [6204] with Implementing Acts to be adopted by 2026.11.29

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Applicability. Emission standards for light-duty vehicles are applicable to all vehicles category M₁, M₂, N₁ and N₂ with a reference mass not exceeding 2610 kg (Euro 5-7). EU regulations introduce different emission limits for compression ignition (diesel) and positive ignition (gasoline, NG, LPG, ethanol,...) vehicles. Diesels have more stringent CO standards but are allowed higher NOx. Positive ignition vehicles were exempted from PM standards through the Euro 4 stage. Euro 5/6 regulations introduce PM mass emission standards, equal to those for diesels, for positive ignition vehicles with DI engines.

EU Member States may introduce tax incentives for early introduction of vehicles that comply with future emission standards.

Fuels. The 2000/2005 standards were accompanied by an introduction of more stringent fuel regulations that require minimum diesel cetane number of 51 (year 2000), maximum diesel sulfur content of 350 ppm in 2000 and 50 ppm in 2005, and maximum petrol (gasoline) sulfur content of 150 ppm in 2000 and 50 ppm in 2005. “Sulfur-free” diesel and gasoline fuels (≤ 10 ppm S) had to be available from 2005 and became mandatory from 2009.

Emission Testing. Emissions are tested over the Worldwide harmonized Light vehicles Test Cycle (WLTC) chassis dynamometer procedure, which replaced the earlier NEDC test. Real Driving Emissions (RDE) testing requirements have been phased-in from 2017 to control vehicle emissions in real operation using emissions testing conducted outside of the laboratory.

Emission Standards

EU emission standards are summarized in the following tables. All dates listed in the tables refer to new type approvals (TA). The EC Directives also specify a second date—one year later, unless indicated otherwise—which applies to first registration (FR, entry into service) of existing, previously type-approved vehicle models.

Phase-In of Euro 5/6 Requirements. A number of requirements have been added or modified after the initial Euro 5/6 effective dates. Several sub-stages of the Euro 5/6 standards can be defined, including:

• Euro 5a: Excludes revised measurement procedure (PMP) for PM, PN standard and flex fuel vehicle low temperature emission testing with biofuel;
• Euro 5b: Full Euro 5 emission requirements including PMP measurement procedure for PM, PN standard for CI vehicles and flex fuel vehicle low temperature emission testing with biofuel;
• Euro 6a: Excludes PMP measurement procedure for PM, PN standard and flex fuel vehicle low temperature emission testing with biofuel (this stage applicable to vehicles that meet Euro 6 standards ahead of regulatory deadlines);
• Euro 6b: Euro 6 emission requirements including PMP measurement procedure for PM; PN standards (preliminary values for PI vehicles); and flex fuel vehicle low temperature emission testing with biofuels (E10 and B7);
• Euro 6c: Euro 6b requirements plus final PN standards for PI vehicles; RDE NOx testing for monitoring only; OBD Euro 6-2; use of E10 and B7 reference fuels.
• Euro 6c-EVAP: Euro 6c requirements plus revised evaporative emissions test procedure.
• Euro 6d-TEMP: Euro 6c requirements plus RDE type approval testing against ‘temporary’ conformity factors (NOx = 2.1, PN = 1.5).
• Euro 6d-TEMP-EVAP: Euro 6d-TEMP requirements plus revised evaporative emissions test procedure.
• Euro 6d-TEMP-ISC: Euro 6d-TEMP requirements plus new ISC procedure, including RDE ISC, type 4, and type 6 tests.
• Euro 6d-TEMP-EVAP-ISC: Euro 6d-TEMP-ISC requirements plus new 48h evaporative test procedure.
• Euro 6d: RDE testing against ‘final’ conformity factors (NOx = 1.43, PM = 1.5) plus revised evaporative emissions test procedure.
• Euro 6d-ISC: Euro 6d requirements plus 48h evaporative emissions test procedure and new ISC procedure.
• Euro 6d-ISC-FCM: Euro 6d-ISC requirements plus on-board fuel/electric energy consumption monitoring (OBFCM or just FCM) requirements for M1 and N1 ICE-only, hybrid and plug-in hybrid vehicles. End of series flexibilities by member states allowed vehicles meeting earlier sub-stages to still be sold after Euro6d-ISC-FCM requirements became effective to offset the impacts of the Covid-19 pandemic on the auto industry.
• Euro 6e: Euro 6d-ISC requirements plus RDE compliance considering updated PEMS error margins (NOx margin of 0.10, i.e., CF = 1.10; PN margin of 0.34, i.e., CF = 1.34); on-board FCM for category N2 vehicles.
• Euro 6e-bis: Euro 6e requirements plus increased extended ambient conditions for RDE compliance (the upper RDE temperature limit for moderate temperature changes to 35°C from 30°C and the upper limit for extended temperature to 38°C from 35°C), Auxiliary Emission System (AES) flag and updated utility factor for vehicles with off-vehicle charging using updated assumptions.
• Euro 6e-bis-FCM: Euro 6e-bis requirements plus updated utility factor for vehicles with off-vehicle charging using FCM data.

Emission Testing

Test Procedures. Emissions are tested over a chassis dynamometer test cycle and expressed in g/km (except PN, which is expressed in 1/km). Over the time, there have been several changes to the regulatory emission test cycles:

• ECE 15 + EUDC: The original EU test cycle (also known as the MVEG-A test), including urban and extra-urban segments, performed from a hot start.
• NEDC: Effective from 2000 (Euro 3), the ECE 15 + EUDC test was modified to eliminate the 40 s engine warm-up period before the beginning of emission sampling. This modified cold start test was referred to as the New European Driving Cycle (NEDC) or as the MVEG-B test.
• WLTP: The Worldwide harmonized Light vehicles Test Procedure (WLTP) and the corresponding Test Cycle (WLTC) [3635][3636] replaced the NEDC procedure. The transition from NEDC to WLTC occurs over the following schedule:
  • September 2017—WLTP type approval testing is introduced for new car types. Cars approved using the old NEDC test can still be sold.
  • September 2018—All new vehicles must be certified according to the WLTP test procedure.
  • January 2019—All cars at dealerships should have WLTP-CO₂ values only (with some exceptions for a limited number of vehicles in stock). National governments should adjust vehicle taxation and fiscal incentives to WLTP values.

During the transition period, compliance with the existing NEDC-based CO₂ targets is determined using the CO2MPAS correlation tool. In the 2020 timeframe, the NEDC-based CO₂ targets were converted to WLTP targets of comparable stringency.

The Euro 5/6 implementing legislation introduced new PM and PN emission measurement methods developed by the UN/ECE Particulate Measurement Programme (PMP). The new PM mass measurement method is similar to the US 2007 procedure. The regulatory PM mass emission limits were adjusted to account for differences in results using the old and the new method. PN emissions are measured over the NEDC/WLTC test cycle using the PMP particle number method [UN/ECE Reg. 83 Suppl. 7].

For Euro 7, exhaust emissions test procedures remain largely unchanged from Euro 6. For M1 and N1 vehicles:

• UN Regulation No 154 (UN Regulation No 154—Uniform provisions concerning the approval of light duty passenger and commercial vehicles with regards to criteria emissions, emissions of carbon dioxide and fuel consumption and/or the measurement of electric energy consumption and electric range (WLTP), 02 series of amendments) applies for laboratory exhaust emissions measurements,
• UN Regulation 168 (UN Regulation No 168, Original version) applies for RDE testing, and
• UN Regulation No 154, Level 1A (4-phase WLTP) (02 series of amendments) applies for evaporative emissions.
• Brake particle emissions for M1 and N1 vehicles are tested according to UN Global Technical Regulation No 24.
• Tire abrasion limits for C1 tires will be based on the testing methodologies developed in UN WP.29.

Real Driving Emissions. Since the Euro 6d-TEMP stage, vehicle emissions must be tested on the road, in addition to laboratory testing. The RDE test is performed during vehicle operation using a portable emissions monitoring system (PEMS). The RDE test must last from 90 to 120 minutes. The route must include three segments: urban (< 60 km/h), rural (60-90 km/h) and motorway (> 90 km/h), in that order and with respective shares of one third. Each segment must cover a distance of at least 16 km.

NOx emissions must be measured on all Euro 6 vehicles—passenger cars and light-commercial vehicles. On-road PN emissions are to be measured on all Euro 6 vehicles which have a PN limit set (diesel and GDI). CO emissions also have to be measured and recorded on all Euro 6 vehicles. RDE emission limits are defined by multiplying the respective emission limit by a conformity factor (CF) for a given emission.

Defeat Devices. For light-duty vehicles, EU regulations define a ‘defeat device’ as:

any element of design which senses temperature, vehicle speed, engine speed (RPM), transmission gear, manifold vacuum or any other parameter for the purpose of activating, modulating, delaying or deactivating the operation of any part of the emission control system, that reduces the effectiveness of the emission control system under conditions which may reasonably be expected to be encountered in normal vehicle operation and use;

The regulations prohibit defeat devices but provide situations under which the prohibition does not apply. This allows manufacturers the option of disabling emission control system components to protect the engine/vehicle and to facilitate starting. However, the regulations do not clearly define ‘emission control system’, a critical aspect of the defeat device definition. A definition is given in the context of the OBD system as:

the electronic engine management controller and any emission-related component in the exhaust or evaporative system which supplies an input to or receives an output from this controller

It is important to note that this definition does not include features such as fuel system parameters, combustion system design and the EGR system.

EU regulations are unclear on how manufacturers are required to apply for an exemption to the defeat device prohibition.