New Zealand vehicle emissions and energy economy data is based on the newer international vehicle emissions and fuel economy testing standard – the Worldwide Harmonised Light Vehicles Testing Procedure (WLTP).
WLTP replaced the longstanding NEDC (New European Driving Cycle) and similar testing standards which are widely considered to be out of date and inconsistent with real-life driving.
The WLTP is a worldwide standard for testing fuel economy, CO2 emissions and electric vehicle (EV) range of passenger and light commercial vehicles. It is a standardised laboratory test based on real driving data and a modified test cycle with stricter specifications to provide a more robust basis for calculating vehicle efficiency.
WLTP testing better reflects actual driving conditions to allow consumers to directly compare the emissions and energy consumption of different vehicle makes and models. While WLTP provides more realistic data, it does not necessarily represent the actual emissions and energy economy an individual driver will achieve. Actual fuel economy may vary due many factors including individual driving styles, traffic and weather conditions, vehicle loading, vehicle maintenance and tyre pressures.
Key differences between WLTP and NEDC testing standards
- The WLTP drive cycle is designed to reflect a wide range of typical daily driving ranging from congested city traffic to higher speed motorway driving.
- The WLTP moves from NEDC's single test cycle of 20 minutes to a longer dynamic test cycle with a longer route and includes roughly half simulated urban driving and half extra-urban .
- WLTP uses four speed phases: low (up to 60 km/h), medium (up to 80km/h), high (up to 100 km/h) and extra high (over 130km/h). The extra high speed phase is excluded in New Zealand as it is not relevant to local driving.
- Unlike NEDC, WLTP takes into account vehicle models with different options — for example, larger wheels and tyres, sunroofs and body kits can all have an effect on fuel economy.
- The WLTP also allows for varying gearshift points with braking, stopping, or accelerating being more representative of real-life driving.