The number of new near-zero-emissions diesel trucks on the road increased 10.2% between 2021 and 2022, according to the Diesel Technology Forum. These are trucks using advanced diesel technology manufactured in the 2010 and later model years.

According to DTF’s analysis of S&P Global Mobility TIPNet Vehicles in Operation Data as of December 2022, diesel dominates the trucking sector, and the population of near-zero-emissions diesel technology trucks is growing:

• They make up 57% of all commercial diesel trucks (Class 3-8) on the roads today. These trucks are equipped with particulate filters and selective catalytic reduction systems (SCR) that achieve near-zero levels of emissions. That’s a 10.2% increase in one year (2022 vs. 2021).

• 65.7% of all commercial diesel trucks (Class 3-8) on the road are 2007 and newer and are equipped with particulate filters so they achieve near-zero emissions for particulates.

"I've had a great opportunity to watch diesel’s trajectory from the late '80s to where we are today," Allen Schaeffer, DTF executive director, told HDT Equipment Editor Jim Park in an interview for the HDT Talks Trucking video podcast. "It's been fantastic watching the technology evolve. We're all reaping the benefits of cleaner air."

Schaeffer pointed out that there nearly 7 million new-technology diesel trucks are on the roads, delivering goods and services with near-zero emissions. Nationwide, for every electric commercial truck on the road, there are nearly 1,100 powered by internal combustion engines, he added.

According to the analysis, internal combustion engines (diesel, gasoline, natural gas, and propane) power about 99.9% of the nation’s trucking fleet.

"As the trucking industry explores new fuels, including all-electric and fuel cell technology, it is clear that diesel and other internal combustion engines are going to continue to play a dominant role for years to come,” Schaeffer said in a release.

California Ranked 35th in Latest Clean Diesel Adoption

The study found that Indiana ranks first of the states for the highest percentage of registrations of 2010 and later model year near-zero emission diesel trucks (73.2%). Next in the rankings are:

• Utah (66.2%)

• Pennsylvania (66%)

• District of Columbia (65.4%)

• Texas (63.6%)

• Oklahoma (62.6%)

• Florida (62.3%)

• Illinois (60.6%)

• Louisiana (59.2%)

• Wisconsin (59.1%).

California lags the national average, taking the 35th spot (51.6%).

Nevertheless, there are 125 times more new-generation advanced diesel trucks on the road in California than electric trucks.

"California has been a laggard in the past seven or eight years that we've done this research," Schaeffer told HDT. "I will say, to their credit, that they have moved up quite a bit in terms of the rate of change. But it’s no secret that if you're a trucker in California you're feeling like your business is under threat."

Schaeffer believes a higher cost of operating in California has contributed to fleets hanging on longer to some of the older technology. "Many haven't been able to invest [in newer trucks] because of the economic situation, the lack of certainty, the regulations, and for some, knowing they will have to switch to something brand new, more expensive, and more complex."

Diesel Advancements

Diesel technology has fundamentally transformed over the last decade, with advancements leading to achieving near-zero emissions beginning with the 2010 model year. Its continued dominance in trucking reflects diesel’s record of continuous improvement and low-cost operati

The next milestone for advanced diesel technology is emerging in California in 2024 and other parts of the country in 2027. That next generation of diesel will further reduce NOx emissions by an additional 50-80% over current models.

No other fuel yet matches the full combination of what the newest generation of diesel technology offers, according to DTF: efficient performance, reliability, durability, low-cost operation, high market value for used products, maximum driving range, flexibility in utilization, routing, and ready access to servicing, parts and fueling throughout the nation.

Decarbonization Means More Than ZEVs

“Decarbonizing the economy will take time and require many different types of solutions for different sectors," said Schaeffer in a news release. "There isn’t a one-size or one-fuel fits all answer. In the meantime, accelerating the turnover of the existing fleet, continued improvement of internal combustion engines, and utilizing low-carbon renewable fuels is just as important as a zero-emission vehicle approach to help achieve meaningful progress toward climate goals."

"I think that we have to be careful not to put too much into the basket of all-electric, zero-emission vehicles, without giving any credibility to any other solution," Schaeffer told HDT.

"I think we're going to be surprised by the next generation of diesel engines, and the other types of internal combustion engines, like natural gas or renewable natural gas," he added, pointing out as well that renewable diesel fuel is a literally a drop-in replacement. "There's so many ways to reduce greenhouse gas emissions and help keep our economy humming without waiting for new technologies that we're not yet sure will even work. I'm excited about the future."