WHAT IS WLTP AND HOW DOES IT WORK?
LABORATORY TESTS FOR PASSENGER CARS MEASURE…
Thus there was no incentive to lower the actual weight of an example sitting in the middle of the band. In WLTP, both the lightest (most economical) and heaviest (least economical) versions are tested. WLTP will also factor in the effect of options that can be specified and produce figures for individual examples. Currently, there is a lot of activity at rolling roads around the world as car makers measure their cars to the new standard and also quantify the impact of options such as wider wheels and tyres.
What will be the effects of WLTP? Claimed fuel economy figures for all cars will drop, and CO2 emissions will rise. Currently, we are in a transition period where figures for new cars can be found for both NEDC and WLTP, but from September this year all new cars sold will have to have a WLTP rating. An equivalent NEDC CO2 rating can still be used for calculating new-car tax but, according to the VCA (Vehicle Certification Agency), ‘at some point’ only the WLTP rating will be used. If at this unspecified point the UK government CO2 tax bands haven’t changed to reflect this, new-car buyers will be paying more tax, even though the car’s emissions have not changed.
There may be more tax to be paid because of options chosen too, as their effect on CO2 emissions will be included
in that car’s rating. Buyers who in the past might have splashed any left-over budget on wider wheels and tyres might think again because they’re a doublewhammy, increasing rolling resistance and aerodynamic drag. Options with a neutral or beneficial CO2 effect might become more popular– low-rollingresistance tyres and aero kits. Remember the Polo Bluemotion?
Perhaps the new test will also produce more realistic economy numbers for turbocharged engines. Currently, they look good in the NEDC test because they can be set up to spend very little of the test on boost. Maybe very efficient, naturally aspirated engines will see a revival, which would be good for enthusiasts because efficiency means more power as well as economy. There is a greater incentive to make cars lighter, too, and as mentioned earlier, that’s good for overall dynamics and, so, good for us enthusiasts.
Buyers who in the past might have splashed any left‑over budget on wider wheels and tyres might think again