This report assesses progress in 2018 toward implementing the Climate and Clean Air Coalition's (CCAC) global strategy to introduce low-sulfur fuels and cleaner diesel vehicles. The rapid reduction of diesel black carbon emissions is one element of a strategy proposed to reduce near-term climate warming by an average of 0.5°C over 25 years. To achieve this target, emissions of black carbon from all sectors must fall to 75% below 2010 levels by 2030. The Heavy-Duty Vehicles (HDV) Initiative of the CCAC released its global strategy in 2016 with the aim for all countries to implement vehicle emissions and fuel quality requirements equivalent to Euro 4/IV by 2025 and Euro 6/VI by 2030. This study finds that this strategy can reduce diesel black carbon emissions to 88% below 2010 levels by 2040 but that higher ambition—equal to Euro 4/IV implementation by 2021 and Euro 6/VI no later than 2025—is necessary to meet the emissions reduction and temperature targets.