CAP HPI has found an average rise of 10% in vehicle CO2 emissions following the introduction of the new Worldwide harmonised Light vehicles Test Procedure (WLTP).

WLTP CO2 emission and MPG testing is now being phased in. The UK government has said that it will retain the ‘old’ New European Driving Cycle (NEDC) vehicle testing procedure for tax purposes until April 2020.

However, during the current ‘transitional period’ vehicles tested to WLTP protocols are ‘converted’ into a so-called NEDC-correlated value using a European Commission-produced mathematical tool.

The CAP HPI study of more than 600 models examined emissions data between September 2017 and May 2018.

The data revealed that:

  • Diesel vehicles increased by 12.6%,
  • Petrol by 7.3%,
  • Petrol/plug-in hybrid by 27.3%
  • and petrol hybrid by 7.8%.

Andrew Mee, senior forecasting editor at CAP HPI, said: “The industry is already seeing the impact of WLTP as some models are removed from the market and options are rationalised. We expect to see the fleet mix change over the coming months with drivers shifting away from models with large CO2 and benefit-in-kind tax increases.” 

The WLTP legislation aims to provide customers with a more detailed view of how a vehicle performs in real-world driving concerning MPG and CO2.