More than 40 percent of all medium- and heavy-duty diesel commercial trucks in operation in the United States — 4 million of 9.5 million diesel trucks — are now equipped with newer technology clean diesel engines, according to a new Diesel Technology Forum (DTF) analysis.
The report includes IHS Automotive vehicles in operation representing Class 3-8 diesel trucks from Model Year 2007 through 2015 in all 50 states and the District of Columbia. Beginning in 2007, all heavy-duty diesel trucks sold had to meet particulate emissions levels of no more than 0.01 grams per brake horse-power hour (g/HP-hr.) — a level near zero.
“The U.S. trucking fleet is transitioning to newer clean diesel technology, which means immediate fuel savings, lower greenhouse gas emissions and cleaner air,” said Allen Schaeffer, executive director of the Diesel Technology Forum.
“This newest generation of clean diesel trucks have nitrogen oxides (NOx) emissions that are 99 percent lower than previous generations along with 98 percent fewer emissions of particulate matter, resulting in significant clean air benefits throughout the U.S.
“Because diesel overwhelmingly dominates the heavy-duty truck sector and is also the No. 1 power source for medium-duty vehicles, the transition to newer generations of clean diesel technology is significant. Beyond the clean air benefits, Model Year 2010 and newer trucks also achieve three to five percent improvements in fuel economy and lower emissions of greenhouse gases.
Schaeffer said there are now four states – Indiana, Utah, Oklahoma and Texas – where more than 50 percent of the registered diesel trucks are the newer cleaner trucks. And in 2015, Oregon had the largest increase in the nation of newer diesel truck registrations with a 35 percent increase over 2014.
California has the largest fleet of commercial truck registrations on an absolute number basis; however, it ranks near the bottom for adoption of newer trucks on a percentage basis, based on the analysis.
In December 2000, EPA promulgated a rule that established stringent standards designed to reduce emissions from on-road heavy-duty trucks and buses by up to 95 percent and to cut the allowable levels of sulfur in diesel fuel by 97 percent by 2010. To achieve these new standards, the new clean diesel system relies on an efficient engine and combustion system utilizing the most advanced fuel-injection, turbocharging and engine management strategies coupled with advanced emissions controls and after-treatment technologies including particulate filters and selective catalytic reduction (SCR) systems, all running on ultra-low sulfur diesel fuel.