Clean vehicle retrofit accreditation scheme

There are currently no CVRAS approved retrofit emission control systems for pre-Euro 4 petrol cars and we do not expect any to come to market in the foreseeable future. The Euro 4 standards for petrol cars came into effect between 2004-2006 and generally cars first registered with the DVLA after 2005 meet the Euro 4 standard. This means cars that are up to 18 years old are generally compliant for a CAZ, LEZ or ULEZ.

There are currently no CVRAS approved retrofit emission control systems for pre-Euro 6 diesel cars and we do not expect any to come to market in the foreseeable future. The Euro 6 standards for diesel cars came into effect in September 2015 and generally cars first registered with the DVLA after 2015 meet the Euro 6 standard. This means diesel cars that are up to 8 years old are generally compliant for a CAZ, LEZ or ULEZ.

There are currently no CVRAS approved retrofit emission control systems for pre-Euro 4 petrol vans and we do not expect any to come to market in the foreseeable future. The Euro 4 standards for petrol vans came into effect between 2005-2006 and generally vans first registered with the DVLA after 2005 meet the Euro 4 standard. This means petrol vans that are up to 18 years old are generally compliant for a CAZ, LEZ or ULEZ.

Maybe, there are a number of CVRAS approved retrofit systems for vans. These systems consist of a Selective Catalytic Reduction (SCR) system added to the original Diesel Particulate Filter (DPF), which were fitted to some Euro 5 vans from September 2010 and to most Euro 5 vans from September 2012. You will need to check your van has an approved solution available, as approved systems are specific to the make and model of a van. Older Euro 4 vans would need both diesel particulate filters (DPF) and the selective catalytic reduction (SCR) system to become CAZ, LEZ or ULEZ compliant. There are currently no combined DPF and SCR systems that have been approved for vans. Such systems are complex to fit and can be expensive, so it may be cheaper to buy a second-hand Euro 6 van or pay the charge if entering a CAZ on an infrequent basis. Avoiding driving in a clean air or low emission zone is also possible.

Maybe, there are a number of CVRAS approved retrofit systems for HGVs.

These solutions consist of diesel particulate filters (DPF) and selective catalytic reduction (SCR) systems. These systems are expensive to fit and specific to the make and model of a vehicle. You will need to check your HGV has a CVRAS approved solution available. Generally, retrofitting will make economic sense when a vehicle is expensive to replace, is in service for a longer time, and is a specialist vehicle. Unfortunately, this means there are low volumes of vehicles requiring a retrofit solution, which makes the investment to design, develop, test and approve a system hard to justify.

This is possible, however there are no CVRAS approved re-powers for cars. This kind of conversion would be a DVLA notifiable modification in terms of engine number and engine capacity, but it would not lead to a change in emission values as stated on the vehicle’s V5C document (logbook) unless an expensive full rolling road emissions test is conducted to obtain the new emission values. This test would need to be conducted at a Vehicle Certification Agency (VCA) approved test facility and cannot be conducted at an MOT test centre.

Converting a pre-Euro 4 petrol car to run on liquified petroleum gas (LPG) is possible but it will not result in a change to the values on the V5C document (logbook) or the Euro emission standard, so will not result in an exemption from CAZ charges.

For London’s ULEZ, you can check your vehicle. Charging Clean Air Zones across England currently include:

• Bath
• Birmingham
• Bradford
• Bristol
• Greater Manchester (under review)
• Portsmouth
• Sheffield
• Tyneside – Newcastle and Gateshead

Transport Scotland has their online vehicle checker that allows motorists in Scotland to enter their registration number to see if their vehicle meets LEZ emission standards. Whilst the results are not a guarantee or proof that a vehicle can enter a LEZ, they can provide some guidance in the meantime.

There are several reasons why retrofit systems are not available for cars and vans, however the main reason is a lack of a business case for the retrofit system supplier. It takes a significant investment to design, develop, test and approve a retrofit system, so there needs to be a significant quantity of the vehicle make and model requiring a retrofit solution to cover this investment. Retrofit systems are specific to make and engine, so the number of variants needed to cover the market also prohibits system development. The fact that you can purchase a second-hand petrol car dating back to 2006 (18 years old) that is ULEZ compliant for less than the cost of a retrofit solution makes the business case even tougher.

Retrofit solutions for buses are well-established. Exhaust after-treatment systems combining diesel particulate filter (DPF) and selective catalytic reduction (SCR) technology are the most widely applied. Other technologies include re-powering, where the old engine is replaced with a new engine with lower emissions or replacing diesel engine with an electric or hybrid drivetrain.

There are currently a number of suppliers approved to provide these systems.

Similar to buses, there is diesel particulate filter (DPF) and selective catalytic reduction (SCR) technology applicable to coach retrofit applications. These systems are tested on specific coach test cycle protocol and there are number of approved systems are available from a number of suppliers and more are being added to the approved list.

There are a large number makes and models of coach in service but many are based on the same engines and chassis so your coach may have an approved system available.

This vehicle category is particularly challenging in terms of retrofit technology, due to the diverse range of vehicles, engines and duty cycles in the legacy fleet.

Diesel particulate filter (DPF) and selective catalytic reduction (SCR) technology is used on the majority of new trucks coming off the production lines.

There are currently a number of CVRAS approved solutions for HGV applications and more are being added to the approved list.

Operators are encouraged to submit their vehicle (make, model and engine) details in order for the potential market to be assessed and to help focus developments on the applications that require a retrofit solution.

One of the most challenging vehicle types in terms of emissions performance are refuse collection vehicles (RCVs). This is because their slow speed, stop-start operation pushes exhaust after-treatment systems to the limit.

However, there are a number of approved suppliers that have retrofit systems that can take a Euro V RCV to Euro VI equivalence for the two most common RCVs, namely the Mercedes Benz Econic and Dennis Eagle Elite.

Another potential retrofit solution for RCVs is electrification, and there is currently an approved electric drive train system provider that is CVRAS approved.

Vans and their van derived minibuses were one of the last vehicle categories to adopt the Euro 6 emissions standards, which means there are more Euro 5 diesel vans and minibuses on the roads in legacy fleets.

In general, the cost to replace a van is lower than for HGVs, unless it is a specialised conversion. This, combined with the fact that retrofit solutions can be relatively high in cost and complex to fit, means that it is sometimes cheaper to replace than to retrofit vans.

In order to comply with an Ultra Low Emission Zone (ULEZ), Clean Air Zone (CAZ) or Low Emission Zone (LEZ), you could purchase a second hand Euro 4 petrol van to comply. As retrofit solutions are more suited to niche or specialist vehicles, the electrification or re-power of vans may work as a retrofit solution.

There are a number of approved systems for upgrading Euro 5 vans, minibuses and motorhomes that utilise the existing original equipment (OE).

Black cabs (London taxis) can be subject to specific requirements from licensing authorities and, in some cases, can be exempt from ULEZ, CAZ or LEZ standards. They may also be significant emitters of local pollution and in service for a significant period which makes retrofit a suitable solution to reduce emissions.

There are limited number of CVRAS approved retrofit systems, one involves re-powering with a Euro 6 petrol engine and converted to run on liquid petroleum gas (LPG), another is a retrofit Selective Catalytic Reduction (SCR) system for the Euro 5 Mercedes Benz Vito Taxi.

Due to the cost of a retrofit exhaust after-treatment system and the complexity to fit within passenger vehicles, retrofit may not be a viable option for most vehicle owners. Purchasing a second hand Euro 4 petrol car may be the best solution to comply with an Ultra Low Emission Zone (ULEZ), Clean Air Zone (CAZ) or Low Emission Zone (LEZ).

There is one CVRAS approved solution for the Euro 5 Land Rover Defender model years 2012-2015. The CVRAS is open to receive applications from retrofit system suppliers as the test protocol and standards are set (the same as for vans), however drivers should be aware that only CVRAS-approved systems will be recognised by local authorities implementing an ULEZ, CAZ or LEZ.