What responsibility do companies have to ensure their products don’t worsen air pollution? Truck manufacturers—Daimler Truck, Volvo, Paccar, and Traton—claim none, even as their products play a central role in California’s and the country’s pollution crisis.
The four truck makers filed a lawsuit against California’s Clean Truck Partnership (CTP) in July. They represent over 90 percent of the state’s truck market. Daimler controls 40 percent and Volvo controls 15 percent. However, Daimler sells less than 1 percent of its trucks as electric, and Volvo around 1.7 percent.
In 2023, the California Air Resources Board (CARB) unanimously passed regulations requiring truck manufacturers to transition to zero-emission vehicles by increasing their sales annually. The Advanced Clean Fleets (ACF) regulations are the first of their kind in the world. The same year, the Environmental Protection Agency granted the state a waiver to enact the regulations.
The CPT is an agreement between CARB, the Truck and Engine Manufacturers Association (EMA), and truck manufacturers representing over 90 percent of the state’s truck market to increase the number of zero-emission trucks. It happened after truck makers and their trade association petitioned for relief from the regulations. One of the conditions for relief is that the truck makers would comply with CARB’s emissions standards “irrespective of the outcome of any litigation challenging” them, or CARB’s authority to enforce them.
In June, Congress nullified the ACF with the passing of the Congressional Review Act, which President Trump signed into law. California filed a lawsuit that month challenging Congress’s nullification. Two months later, the Justice Department sued CARB to end enforcement.
California’s Worsening Air Pollution
A coalition of business groups, clean freight advocates, and public health organizations sent a letter in August in support of the Clean Truck Partnership. The letter asked the Engine Manufacturers Association, the four truck manufacturers, and other manufacturers “to stop the silence and undercutting…instead, you must reaffirm your commitment.”
Diesel trucks are only three percent of all vehicles on California’s roads, or two million out of 30 million registered vehicles. However, they cause 86 percent of nitrous oxide and 30 percent of greenhouse gas emissions. Diesel contributes to air pollution. The transportation sector is one of the largest contributors to GHG emissions in the U.S. In California, trucks are the largest source of air pollution from vehicles, accounting for 70 percent of smog-causing pollution and 80 percent of carcinogenic diesel soot.
The Cost of Air Pollution on Health
The ACF regulations help two of the most polluted air basins in the country — the Los Angeles area and the Central Valley. Seven of the top 10 cities with the highest ozone levels in the American Lung Association’s State of the Air report are located in California. For short-term particle pollution (PM2.5), six of the 10 cities listed are in California. Seven out of 10 cities for year-round particle pollution (PM10) are also in California.
The Central Valley has some of the highest asthma rates in the state and nation. When asthma worsens due to air pollution in the Valley, it results in approximately $498,014,124 in annual emergency room visits, according to a 2024 study. It also cost $223,552,720 in hospital admissions the same year.
By supporting the Clean Truck Partnership, truck makers have a clear opportunity—and responsibility—to help reduce air pollution in California. Instead, by prioritizing legal action over solutions, they avoid meaningful change. This lack of accountability means more people like me will be coughing and wheezing as our asthma worsens.
Image by TruckPR on Flickr under Creative Commons license
