Consulting report

Methods of converting the type-approval fuel economy and CO2 emission values of light vehicles: An analysis for New Zealand

All of New Zealand’s light-duty vehicles (LDVs) are imported, and the majority of LDV certifications being processed in New Zealand are based on tests conducted in countries that rely on one of six test procedures. In order for the government to implement a Clean Car Discount and a Clean Car Standard, it needs a formal protocol for normalizing carbon dioxide (CO2) emissions—and, if necessary, fuel efficiency—across test cycles. This consulting report develops methods and algorithms that the country can adopt to determine compliance with LDV low-emission policies on a Worldwide Harmonized Light Vehicles Test Procedure (WLTP) CO2-equivalent basis. Such methods and algorithms are expected to be reasonably robust and fair for all light vehicle segments; relatively easy to understand and use; the best fit for New Zealand’s situation; and capable of covering all light vehicles newly registered or re-registered in New Zealand.

As described in detail in Section 5.1, the report recommends that the 3-phase (3P-WLTP) serve as the basis for standardization in New Zealand and suggests algorithms to convert data from other cycles to the 3P-WLTP. The report can be viewed and downloaded from the Ministry of Transport’s website.