Fuel types

In order to work out the running costs for your car, you'll need to consider what type of fuel your car uses.

Diesel and petrol vehicles

Diesel cars tend to use less fuel than petrol vehicles and do more miles per gallon (mpg) or litre, when doing long distance or motorway driving. However, diesel cars may be more expensive than petrol, and generally have a higher Advance Payment .

Engines powered by diesel generally emit less CO2, but they do produce more air quality pollutants than petrol engines. However, to counteract these effects, many diesel cars have Diesel Particulate Filters to remove sooty particles from the exhaust gases of vehicles.

There are advantages and disadvantages to both diesel and petrol cars so it is important to choose the right vehicle for you. Generally speaking, if you mainly drive long distances or on motorways, then a diesel engine might be good for you. On the other hand, if you spend more time in town doing short journeys at lower speeds, you might be better off with a petrol engine.

Hybrid and electric vehicles

Hybrid vehicles have a combination of an electric motor and standard combustion engine to reduce vehicle emissions.

We have a selection of hybrid vehicles available on the Scheme, including the Toyata Prius, Mini Countryman, Mitsubishi Outlander and Kia Niro as plug-in hybrids.

Electric cars are the ultimate eco-friendly choice as they have zero exhaust emissions. However, as they have to be recharged regularly, they are not suitable for everyone. Electric cars can travel a certain distance before needing to be recharged and in order to have a home charging point fitted, you will need to have access to off-road parking, such as a private driveway or garage. We are delighted to offer the Smart Fortwo and Forfour EQ range, BMW i3, Hyundai IONIQ and the Renault Zoe as full electrics

Miles per gallon

The mpg figure can help you decide how economical a car may be in terms of fuel consumption. However, it’s worth noting that fuel consumption figures should be used for comparison purposes only as they may not be the same as the figure actually achieved. This is because of the way they are calculated.

How are official mpg figures calculated?

There have been various standardised tests to calculate the miles per gallon (mpg) figure for each car over the years. The current method (monitored by the Department of Transport) sees cars being tested in a laboratory.

The car is fixed on a set of rollers known as a rolling road, and a series of drills including braking and accelerating are performed; these are designed to replicate types of driving.

The exhaust gases released are measured using special equipment. From this, the emissions ratings are calculated as well as the fuel economy (mpg figure).

This test involves two parts:

The Urban Cycle

This begins with a cold engine start; the car is stopped and started a number of times to replicate town driving. The maximum speed is 30mph and the journey lasts two and a half miles.

The Extra Urban Cycle

This lasts for 4.3 miles at speeds of up to 75mph designed to replicate out-of-town driving. The results are used by car manufacturers. You will also see a mph figure for each model on the Car Search.

The effect of these tests

The tests are designed to provide standardised and comparable results which can be repeated for every car.

Because they are carried out in a lab, they may not cover the huge range of variables which affect the fuel economy in real-world driving conditions, including different driving styles, travel habits (for example if you regularly drive on a motorway), things like extra weight from passengers, luggage or optional extras fitted to the car and so on.

There are calls to reform the way these figures are calculated. Former transport minister Norman Baker admitted there were “limitations to the current test” and that improvements were planned. However, he also added that until European countries agree on a better approach, the existing test was still useful.

Until such change takes place, it is best to treat these figures for comparison purposes only; the actual mpg figures a car achieves will vary because of the above factors.

From 1 January 2019, miles per gallon (MPG) performance is measured using the new Worldwide Harmonised Light Vehicle Test Procedure (WLTP) fuel economy tests, which typically give lower mpg performance values than the old New European Driving Cycle (NEDC) tests. Please consult manufacturer websites for the most up-to-date mpg performance values.

Exhaust emissions

Every car gives off different levels of exhaust emissions. One of the most harmful emissions is carbon dioxide (CO2) and car manufacturers are continually working to reduce this.

All new cars are tested and given a CO2 emission level rating. In line with banding introduced by the government, these range from A (the lowest CO2 emissions) to G (the highest CO2 emissions.) Cars with a CO2 emission level of 100g/km are considered low emission models. There are several low emission models available through the Motability Scheme. Look for the green leaf symbol on our Car Search .

The majority of the low emission cars (bands A and B) are the models with smaller engines and/or body size, making them potentially unsuitable for those who require more space, for wheelchair storage or to carry multiple passengers, for example.

We recognises that one size does not fit all, and we therefore offer greener choices for all class of vehicle. With emission levels differing by up to 65g/km between various small family cars and 100g/km between MPVs, your choice of car model could make a significant difference in your environmental impact.

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