Although the market is turning towards electric and hybrid models we know that these aren’t always the right choice for your business and you might go for a petrol or diesel model in some circumstances.

When choosing a vehicle that has a traditional combustion engine then you will need to think about its CO2 emissions. To help you understand what CO2 emissions are and their importance in making fleet decisions we’ve put together the below guide.

What Are CO2 Emissions?

CO2’s full name is carbon dioxide and it is a gas in the Earth’s atmosphere, which occurs naturally and can also be emitted as a pollutant by a number of different human activities.

Natural levels of CO2 emissions are balanced out in the Earth’s ecosystem through natural processes like trees and plans absorbing the gas through their photosynthesis processes so this was not damaging to the planet. It is human activities that have seen a massive increase in the level of CO2 emissions that has caused a problem for the atmosphere and continues to do so, which is why many countries, companies and individuals are looking to reduce their CO2 emissions. The burning of fossil fuels, including in our combustion engine vehicles is the main contributor of this.

What Causes CO2 Emissions? 

CO2 emissions can be produced in a number of ways but in vehicles they are caused by the burning of fossil fuels, petrol or diesel, in order to create the power needed to move the vehicle. 

Other Vehicle Emissions

Vehicles do not only emit CO2 but they also emit a number of other pollutants. Depending on whether you opt for a petrol or diesel engine, and then the size of it, the amount and type of pollutants they are heaviest in will vary. We take a deeper look at these in the specific petrol and diesel guides if you want to find out more about other pollutants they emit.

CO2 Emission Measurement

Vehicle emissions are heavily regulated to ensure they are producing as low levels as possible to reduce the impact drivers have on the environment.

CO2 is measured by its weight in grams, and when looking at a vehicle’s emission levels this is measured in terms of the grams emitted over a set distance. This is usually grams per kilometre and so you’ll see g/km when looking at the emission values of vehicles with a combustion engine.

The UK is currently aiming for all new vehicles to produce only 95 g/km.

WLTP Testing

The main form of testing new cars in the UK for their emission levels is with World Harmonized Light-Duty Vehicle Test Procedure (WLTP) testing.  

This method replaced previous NEDC testing, which there were concerns about the results not reflecting real world driving conditions and so provided inaccurate emission levels. It’s also a measurement that is designed to be used by manufacturers around the world to give a more uniform and comparable measurement internationally.

In WLTP testing vehicles are tested in a dynamic cycle that is designed to reflect real driving conditions, with the cycle lasting 30 minutes and travelling a distance of 23.23 km. The cycle includes four driving phases with low, medium, high and extra-high speeds as well as a split between urban and non-urban driving.

The average speed during the testing is 46.5 km per hour and the maximum speed is 131 km per hour.

WLTP tests also take into account any additional options added to the vehicle and the impact they will have on the CO2 emissions.

RDE Testing

The Real Driving Emissions (RDE) testing measures other pollutants from the vehicle, and does so on the road rather than in simulated laboratory conditions.

RDE ratings are given alongside WLTP testing and do not currently measure CO2 emissions but may be in the future.

Euro Six

The Euro 6 is a later revision of the Euro 1 EU vehicle emissions targe.

Like the RDE testing Euro 6 measures the other pollutants a vehicle emits including: carbon monoxide, nitric oxide, nitrogen oxide, hydrocarbons and particulate matter like soot.

How to Calculate CO2 Emissions

It can be difficult to calculate the emissions your fleet is producing, especially if there is a number of vehicles in the fleet. 

You can use the government's website to calculate the emission levels of particular vehicles so that you can see whether they are damaging to the environment and need upgrading in order to reduce your business' overall CO2 emissions.

CO2 Tax Implications

The amount you pay in road tax is based on the amount of CO2 the vehicle emits which means the lower the CO2 emissions the lower your tax.

Additionally, any diesel vehicles that do not meet RDE2 compliant levels will have to pay a higher rate.

For any vehicles in your fleet that are leased you will not need to worry about road tax as this is paid by the funder as they are the legal owners.

Another reason you’ll want to encourage your drivers to take up a lower emitting vehicle is because the company car tax rates that you and your employees will pay is based on the CO2 emissions of the car. We’ve got a more extensive breakdown of how this will affect the amount you pay here.

CO2 and MOT Testing

If any of your fleet is over three years old it will need to have an MOT completed annually. During the MOT the vehicle will also be tested for emissions and if they do not meet the required levels then it will fail its MOT. Testing for new cars is done using a meter to get accurate readings. 

CO2 and Low Emission Zones

Across the country we have seen towns and cities follow London’s lead and start the process of implementing low emission zones (LEZs) and clean air zones (CAZs) where there are restrictions on the vehicles that can enter them or those that do not meet set emission standards may have to pay a charge.

The RAC have this useful map that shows all the clear air schemes across the UK if you are concerned about whether there is a clean air zone in your area.

How Will CO2 Emissions Affect Our Fleet Decisions?

It’s clear that CO2 emissions have an impact for vehicle owners as well as the wider environment and so you’ll want to consider the CO2 emissions of a vehicle when deciding whether it’s the right choice for your fleet.

The tax implications of CO2 with road tax if you are purchasing vehicles for your fleet are a key reason for considering the CO2 levels emitted by vehicles before deciding on the right option.

For both you and your drivers lower CO2 emitting vehicles have cheaper company car tax, and so you should communicate that to your drivers to help them understand the link between the two.

Opting for lower CO2 models will also help to reduce the business’ overall carbon footprint.

Top Five Tips to Reduce CO2 Emissions

There are several things that you and your drivers can do to help reduce vehicle CO2 emissions. We’ve rounded up our top five tips that are easy for any driver to do:

1. Keep up to date with the vehicle servicing

2. Remove any roof and bike racks when not in use

3. Drive carefully and avoid harsh acceleration and braking

4. Don’t sit with the engine running

5. Regularly check the tyre pressure and keep at the optimum level

What's the Future for CO2 Emissions?

The UK government has put in place a ban on the sale of new vehicles that produce any emissions from 2030 which is why we're seeing so many manufacturers bring out EV models. Currently, there are various schemes in place to help businesses and drivers transition to an EV but as we get closer to this ban date the availability of such schemes is changing and reducing. 

Though it's not been confirmed it's likely that once new models are all zero-emissions the government will then look to drivers of older higher polluting models and ways to help them upgrade to new non-polluting models. 

When the time comes to upgrade any of the vehicles in your fleet you might also want to consider an electric or hybrid model. We know that this might not always be the right choice for your business or that particular vehicle need and you can call on 01722 322 888 and we would be happy to discuss your business needs and what fuel type would work best for you.


Contact Wessex Fleet