(13)Furthermore, the current emission limits for heavy-duty vehicles were adopted in 2009 on the basis of the available technology at that time. Since then, technology has advanced and the level of emissions achievable with a combination of current technologies is much lower than that achievable more than 15 years ago. That technological progress should be reflected in emission limits based on existing state-of-the-art technology and knowledge of pollution controls and for all relevant pollutants.