WLTP will give car buyers more realistic fuel economy and emissions values when buying their new car
New WLTP emissions testing for new cars and vans looks set to shake up the motor industry

What is WLTP?

WLTP is a new, more realistic test procedure for measuring fuel consumption and CO2 emissions for new cars, as well as their pollutant emissions directly on the road by the Real Driving Emissions (RDE) test. Here’s a simple guide to the new procedure and what it means for motorists in Ireland.

What does WLTP stand for?

Worldwide harmonised Light vehicle Test Procedure.

What does WLTP measure?

Under EU law, all new passenger cars must undergo emissions testing. WLTP is a new laboratory test that measures fuel consumption and CO2 emissions for passenger cars, and their pollutant emissions. It replaces the New European Test Cycle (NEDC) that was used since 1992.

Why the change?

The WLTP is a stricter set of test conditions that will give more realistic fuel consumption and CO2 emission values for the benefit of consumers. NEDC was based on theoretical driving; the new procedure is based on real driving data that better reflects on-road performance.


  • Dynamic cycle more representative of real driving vs single test cycle
  • 30 mins cycle time vs 20 mins cycle time
  • 23.25 km cycle distance vs 11 km cycle distance
  • 4 more dynamic driving phases vs 2 driving phases
  • 46.5 km/h average speed vs 34 km/h average speed
  • 131 km/h maximum speed vs 120 km/h maximum speed
  • Influence of optional equipment on CO2 and fuel performance considered under new procedure
  • Different gear shift points for each vehicle vs fixed gear shift points
  • Measurements at 23 degrees Celsius, CO2 values corrected to 14 degrees Celsius vs measurements at 20-30 degrees Celsius

What’s the impact?

Due to more realistic test conditions, the fuel consumption and CO2 emissions measured under the new procedure are in many cases higher compared to those measured under the NEDC. In countries like Ireland that follow CO2 based taxation, this obviously will have an impact on the price of our cars and motor tax if adjustments are not made by national governments. The new test also measures the influence of optional equipment on CO2 and fuel economy, so these values may vary for cars within the same model range depending on vehicle specification.

When does WLTP start?

The new procedure is being phased in between 2017 and 2020. It’s in the news now because from 1st September 2018, all new cars must be approved under the WLTP test procedure. In the transitional period, new cars will have both a WLTP and a calculated NEDC equivalent CO2 and consumption value, the latter which can still be used for vehicle registration and taxation purposes until full bedding in of WLTP in 2020. From 1st January 2019, the EU recommends that only fuel consumption and CO2 emissions values under the new procedure are used for consumer information purposes.

Does WLTP apply to vans?

Yes it does. From 1 September 2018 manufacturers will have to provide WLTP values for newly introduced light commercial vehicles.

WLTP in Ireland

WLTP values for CO2 emissions and fuel consumption, and the calculated NEDC values that can be used during the transition to full WLTP, will in many cases be higher compared to the NEDC values for the same car. In Ireland, this could mean that cars become more expensive to buy and to tax as we transition. Some brands are predicting increases of a few hundred euro based on the NEDC-correlated values. SIMI is calling on the Government to review VRT Bands in the next Budget to accommodate for higher, more realistic CO2 emissions on new cars as a result of the new emissions testing procedure, so that the consumer does not incur additional costs. Industry experts predict that some models could be discontinued if they are no longer deemed to be suitable for the Irish market based on rising costs as a result of CO2 based taxation. However there is still uncertainty in the industry to the full impact, with many insiders taking a ‘wait and see’ approach.

Which cars are WLTP compliant?

Up to date information can be found from the manufacturers’ websites. Some manufacturers have already released revised fuel economy and emissions data for their range of vehicles.

For more information, the European Automobile Manufacturers’ Association (ACEA) has created this resource.

Caroline Kidd