On-Road Vehicles

Roughly 34% of diesel exhaust in the Puget Sound region comes from on-road diesel engines, which include light-duty trucks and personal cars; medium-duty vans and small buses; and heavy-duty vehicles, such as trucks, buses, and waste haulers.

We help fleets reduce diesel emissions from on-road engines through:Graph of diesel emission sources.

  • Best practices
  • Cleaner fuels
  • Retrofit technologies (exhaust and crankcase retrofits and preheaters)
  • Vehicle replacements

*Note: For emissions inventory purposes, our agency includes cargo-handling equipment in the maritime sector and not in the off-road sector.

Projects

Recent projects to reduce diesel pollution from on-road vehicles primarily have focused on replacing or retrofitting older, dirtier vehicles with cleaner, newer vehicles or engines.

ScRAPS Program: Scrappage & Retrofits For Air In Puget Sound

Working with The Northwest Seaport Alliance, we scrapped over 400 old, dirty heavy-duty diesel trucks at the Port of Seattle and Port of Tacoma and replaced them with newer cleaner trucks. 

  • Project Period: 2014 - 2017
  • Air Pollution Reductions:
    • Particulate Matter (PM 2.5) - 5 tons per year
    • Nitrogen Oxides (NOx) - 78 tons per year 
  • Funding:
    • $1,500,000 - Port of Seattle
    • $350,000 - Washington Department of Ecology
  • Project Manager: Beth Carper


Fleet Vehicle Retrofits

We retrofitted more than 650 public and private fleet vehicles, including fire and first responder vehicles, city and county fleet vehicles, and waste haulers. 

  • Clean Air Strategies: Diesel oxidation catalysts and crankcase filters
  • Air Pollution Reductions:
    • Particulate Matter (PM 2.5): 2 tons per year
  • Project Period: 2003 through 2008
  • Funding:
    • $946,000 - Puget Sound Clean Air Agency
    • $356,000 - Environmental Protection Agency
  • Project Manager: Beth Carper


Diesel Electric Hybrid Truck Replacements

As part of the $15M Western Washington Clean Cities Petroleum Reduction Project, this sub-project reimbursed utilities for the cost difference between a conventional diesel bucket truck and a diesel-electric hybrid bucket truck.

  • Clean Air Strategies: Replacement and Alternative Fuels
  • Air Pollution Reductions:
    • Particulate Matter (PM 2.5): 40 pounds per year 
    • Carbon Dioxide (CO2) Equivalents: 13 tons per year 
  • Project Period: 2010 to present
  • Funding:
    • $1.1 million - U.S. Department of Energy
  • Project Manager: Beth Carper


Waste-Hauling Truck Replacements

As part of the $15M Western Washington Clean Cities Petroleum Reduction Project, this sub-project reimbursed waste hauling fleets for the cost difference between a conventional diesel truck and a natural gas or hydraulic-hybrid natural gas truck.

  • Clean Air Strategies: Alternative Fuels
  • Air Pollution Reductions:
    • Particulate Matter (PM 2.5): 300 pounds per year 
    • Carbon Dioxide (CO2) Equivalents: 30 tons per year 
  • Project Period: 2011 to present
  • Funding:
    • $406,000 - U.S. Department of Energy