I do not believe you should…

I do not believe you should scrap the light duty vehicle testing, but raise the standards prospectively, so that vehicle manufacturers are incentivized to continue making cars fuel efficient. Scrapping testing for light duty cars may lead to manufacturers relaxing standards or having incentive to do so. Furthermore, the current standards are fairly old - with the development of efficiency technology and introduction of electric vehicles, I believe it makes sense to find that the old light duty car standards would benefit from updating.