California air quality regulators have outlined plans for the trucking industry to bear a large share of the burden for cleaning up the dirtiest air in the nation.

In proposed regulations revealed this week, the staff of the California Air Resources Board proposed implementation of a low-NOx engine standard calling for between 100,000 and 150,000 new heavy-duty trucks with special engines to be in use in California by 2023.

So far, only one company, Cummins Westport, builds a low-NOx engine that meets the proposed nitrates of oxygen emissions standard of 0.02 grams per horsepower-mile of operation – a 90 percent reduction from the present standard of 0.2 grams.

The 8.9-liter engine uses compressed natural gas as a fuel and is intended to replace diesels in larger medium-duty trucks. Cummins Westport also is developing low-NOx CNG engines for smaller medium-duty trucks and for some heavy-duty truck applications.

Several other engine manufacturers also are working on low-NOx systems.

Many of the proposals were developed in concert with the recently released California Sustainable Freight Action Plan and are intended to help implement that plan.

The plan, which sets up timelines for regulatory action and sets implementation schedules, is short on specifics: The details are to come as individual programs are brought to the air board directors over the next few years.

The strategy proposal won lukewarm praise from the California Trucking Association. In the past, regulations for cleaner truck emissions have forced trucking operators to spend hundreds of millions of dollars retrofitting existing vehicles.

“But the low-NOx engine proposal supposes we can get there with normal replacement schedules, without retrofitting,” said Chris Shimoda, the trucking group’s policy director. “That’s a step in the right direction.”

Other new equipment policies – specifically increasing use of zero-emission vehicles in short-distance freight movement such as port shuttling and so-called last-mile delivery situations – “are a stretch because none of those vehicles exist for commercial use right now,” Shimoda said.

The trucking association would be talking about those proposals with the Air Resources Board staff before specific implementation deadlines are drawn up, Shimoda said.

Environmental groups are generally supportive of the plan, although several said it doesn’t push hard enough to promote use of zero-emissions vehicles.

The Union of Concerned Scientists wants “a clear signal” that incentives will be used to get freight-moving tractors in the ports of Long Beach and Los Angeles transitioned to electric power as soon as possible, said Don Anair, the group’s clean vehicles program research director.

“There are a lot of measures in this mobile sources strategy plan that we support, but we think they need to go further,” said Bill Magavern, policy director for the Coalition for Clean Air. “There’s not enough in this to get us healthy air in the South Coast,” one of the state’s worst regions for air quality.

The plan relies on zero-emissions vehicles for short-range freight movement. Magavern said he would also like to see the use of near-zero emissions equipment with low carbon, renewable fuels when zero-emissions vehicles are not available.

The strategy proposal addresses efforts to slash emissions from all types of mobile sources including passenger vehicles, commercial trucks and off-road equipment.

Heavy-duty trucks account for 33 percent of the state’s NOx emissions, the proposal says, along with 26 percent of diesel particulate matter that contributes to lung disease and other respiratory ailments. Trucks also are a “significant source” of greenhouse gas emissions, according to the proposal.

It focuses on the two most heavily impacted regions of the state: the South Coast Air Basin, encompassing most of Southern California, and the agricultural San Joaquin Valley.

Truck-oriented strategies in the proposal include:

  • Development this year of clean air certification standards for hybrid truck engines.
  • Tightening exhaust “smoke” limits for required annual diesel inspections and periodic on-road heavy-duty vehicle inspections.
  • Increasing durability requirements necessary for California certification of new truck engines.
  • Petitioning the federal Environmental Protection Agency to propose a national low-NOx engine standard of 0.02 grams by 2017 – for implementation beginning with 2023 model-year trucks and, if the EPA doesn’t do so, to prepare California-only standards with the same timeline.
  • Modifying California’s greenhouse gas emissions requirements for heavy trucks to harmonize with the federal “Phase 2” truck emission regulations expected to be published this summer. The proposal notes that California regulations may be more stringent in some areas than the federal rules because of the state’s “unique” air quality challenges. The only example provided was the potential for “layering on” additional California-specific aerodynamic requirements for truck trailers.
  • Developing an incentive-based truck emissions reduction plan by 2018 and ensuring that existing clean vehicle incentive funding for trucks be used to help truck operators replace older, dirtier equipment.

About The Author

John O'Dell

John O’Dell is a Trucks.com contributing writer, green technology expert and editor of TheGreenCarGuy.com. He previously wrote for Edmunds.com and the Los Angeles Times, and served on the National Research Council committee that authored the seminal report “Transitions to Alternative Vehicles and Fuels.”