Measuring CO2 emissions from commercial road transport only at the tailpipe, depending on the region, could double the true carbon picture in future fuel scenarios. / Heavy-duty commercial vehicles, including coaches and trucks, emit just 950 million tonnes of CO2 annually at the tailpipe, using the tank-to-wheel standard, about 2.5% of global emissions.1 While hydrogen and electricity are often mistakenly seen as zero emission fuels, if all CO2 emissions are taken into account, including well-to-tank, a more realistic carbon picture of these alternative fuels emerges. In Europe, the US and China alone, on average, this would add 45% more CO2 for electricity and 72% more for hydrogen versus conventional diesel, based on today’s energy mix.2