What Do the New WLTP Regulations Mean?

Whilst the buying public generally accept that car manufacturers ‘massage’ their claims of fuel economy, the level of which those figures misrepresent information is perhaps the shocking part, but … and it is a very big but, the manufacturers aren’t actually being dishonest, nor doing anything illegal; they’re simply taking advantage of an archaic system developed in the 1980s that was meant to give consumers more information.

If we think how much technology has changed within that period, is it any wonder that mpg figures, or more specifically, the way that mpg figures are measured is open to interpretation?

Laboratory Testing

Under the New European Driving Cycle (despite the name, this was the process introduced in the ‘80s) a car manufacturer uses laboratory conditions to measure fuel consumption, controlling air temperature, load, speed, humidity … all the factors that can affect fuel usage, it also doesn’t take into account wind resistance, real-world acceleration, gradients … and we wonder why manufacturers tell us that XYZ model will run to 100+ mpg?

The latest regulations, the Worldwide Harmonised Light Vehicle Test Procedure (WLTP) still uses laboratory testing, but simulating the kind of conditions and effects that you’d find outside of a manufacturers test cell. Better yet, further testing procedures are also coming, and these are Real Driving Emissions (RDE) testing; it’s thought that with both sets of legislation coming into force, the claimed mpg figures for any manufacturer will be accurate (some may even say ‘truthful’).


The WLTP should be global, meaning that manufacturers will use the same figures throughout their sales territory, and the figures should have relevance, but certain parts of the European Union and other parts of the world will have the flexibility to apply the tests and procedures in ways that suit their road traffic laws and needs, so the reality is that we could still see some discrepancies (although the figures should be more closely aligned).

Essentially, the WLTP will be divided into four different categories, using different average speeds – low, medium, high and extra high, but the testing will also include a variety of driving conditions, stopping, acceleration and braking for each phase; experts have described the testing as ‘dynamic’.

There will also be testing for each powertrain type – 2WD, 4WD, FWD and RWD using a range of the lightest and heaviest load (least fuel consumption and most fuel consumption).

Going Green

A recent study revealed that hybrid vehicles in particular were as much as 63% down on their claimed manufacturers figures, which considering the vehicles are purchased for their green credentials, makes a mockery of the system, in fact just one of the 39 hybrid models currently available managed to achieve the claimed figure for fuel economy.

That isn’t to say that hybrids aren’t economical, rather that they may not be quite as economical as a consumer may think, and of course, we shouldn’t forget the emissions side of the coin. Whilst it’s true that the new WLTP and RDE regulations will change the advertised or claimed figures, the reality is that nothing will actually change for the consumer – a car can only achieve what it can achieve, and if you’re looking at a specific model, a serious car buyer will already have a good understanding of figures they’re potentially looking at, the new regulations will merely confirm that.

The main differences between the two tests:

Test cycleSingle test cycle Dynamic cycle more representative of real driving
Cycle time 20 minutes 30 minutes
Cycle distance11 kilometre 23.25 kilometre
Driving phases2 phases, 66% urban and 34% non-urban driving 4 more dynamic phases, 52% urban and 48% non-urban
Average speed34 kilometre per hour 46.5 kilometre per hour
Maximum speed120 kilometre per hour 131 kilometre per hour
Influence of optional equipment Impact on CO2 and fuel performance not considered under NEDC Additional features (which can differ per car) are taken into account
Gear shiftsVehicles have fixed gear shift points Different gear shift points for each vehicle
Test temperatures Measurements at 20-30°C Measurements at 23°C, CO2 values corrected to 14°C

Car Buying

If your car buying habits are driven by maximum mpg, you’ll already know that a two-seater sports car with 400+ horsepower is going to be less economical than a wind-tunnel drag-optimised 3-cylinder hybrid, you don’t need small print to tell you that.

Perhaps the best way of learning about a new car purchase is finding the right dealership – a group or dealer that you can trust, it’s about making a connection with the sales professionals, one of trust and understanding, and the knowledge that ‘your’ sales professional is doing the best for you, not for their commission.

Like to find out more about why Helston Garages Group are that kind of dealership? Contact a member of our friendly team today to discuss your needs.

Contact us