Year in Review: Progress towards Decarbonizing Transport and Near-Zero Emissions

<div class="section abstract"><div class="htmlview paragraph">As in the past several years, we provide here an overview of recent major regulatory and technological changes for reducing emissions from the transport and off-road sector. In the past, this review was focused mostly on improvement in engine efficiency and tailpipe emissions of criteria pollutants. However, starting last year [<span class="xref">1</span>] we have increased the scope to broadly address the increased focus on greenhouse gas emissions and the emergence of various non-conventional fuel pathways to achieve the various decarbonization goals.</div><div class="htmlview paragraph">There are two broad themes that are emerging, and which we describe here. Firstly, that we are approaching the implementation of the last of the major regulations on criteria pollutant emissions from cars and trucks, led by Europe, through Euro 7 standards and US, through multi-pollutant standards for light- and heavy-duty vehicles. While electric vehicles are getting much of the headlines, most vehicles sold in the last year still had an internal combustion engine. OEMs therefore must continue to improve upon traditional ICE technologies to meet these upcoming standards, while also investing in alternative powertrains such as hybrids, electrics, hydrogen-powered vehicles, and engines running on renewable fuels. This is reflected in the increasing diversity of topics published and discussed at conferences, which we try to cover. Which brings us to the second theme: several major studies conclude that given the uncertainties of cost, infrastructure readiness, consumer acceptance and decarbonization of upstream energy generation, it is prudent to pursue all these diverse technology pathways. A ban on the sale of new internal combustion engines is one tool, but a limited one given that majority of the emissions are associated with those of the cumulative fleet, which will take decades to turnover.</div><div class="htmlview paragraph">We describe the major regulatory developments along with the implications for technologies, both for light- and heavy-duty vehicles.</div></div>