Delaware.gov logo

Reducing Diesel Emissions



Delaware has several programs designed to reduce diesel emissions, which can have significant negative impacts to overall air quality, from vehicles.

Contact Us

Deanna Morozowich
Division of Air Quality
302.739.9402

Heavy-duty, diesel-powered vehicles can emit nitrogen oxides, fine particulates, and other tailpipe pollutants that contribute to air quality problems.

DNREC oversees anti-idling regulations and enforcement efforts, and participates in national and regional efforts to reduce particulate pollution from vehicles and other sources.

Anti-Idling Regulations

Idling of an on-road vehicle over 8,500 pounds gross vehicle weight for longer than three minutes is, in most cases, prohibited in Delaware. Violators are subject to penalties of not less than $50 and up to $500 for each offense. Subsequent violations carry fines of from $500 to $1,500.

In 2005, DNREC adopted regulations governing Excessive Idling of Heavy Duty Vehicles (7 DE Admin. Code 1145) and the Division of Air Quality’s Environmental Crimes Unit began ticketing operators in violation in September 2006.

Reporting Violations

Report idling violations in Delaware at 1.800.662.8802. Or, for those using Verizon Wireless service, call #DNR.

Heavy duty vehicles subject to this regulation include long-haul and delivery trucks, and transit and school buses. Emergency fire, rescue, and lifesaving vehicles are exempted. Other vehicle operating situations also may fall under the Exemption Section of the regulation.

Delaware is one of more than 25 state and city jurisdictions that have implemented regulations addressing idling time for heavy-duty vehicles. New Jersey and the City of Philadelphia also have established maximum allowable idling time restrictions.

Diesel Emission Reduction Act

Idling trucks

Since 2008, Delaware has participated in the National Clean Diesel Campaign through its funding to install clean diesel technology. These technologies include emissions and idle control devices (Smyrna Rest Area, Truck Stop Electrification facility ), aerodynamic equipment, engine and vehicle replacements, and alternative fuel options.

Projects have included:

  • Adding diesel oxidation catalysts on two ship-to-shore cranes and engine replacements on four product-loading vehicles at the Port of Wilmington.
  • Replacing two propulsion engines on the Wilmington tug.
  • Retrofitting 56 school buses to add diesel particulate filters and/or closed crank case ventilation equipment.
  • Adding diesel particulate filters to 32 municipal public works vehicles.
  • Adding diesel particulate filters on 37 DelDOT dump trucks and replacing a street sweeper with a cleaner version.
  • DNREC Fort Delaware replacing two piston generators with a micro-turbine generator at Fort Delaware State Park.
  • Created 24 electrified parking spaces at the Smyrna Rest Area.

The SmartWay Program

In 2016, the Division of Air Quality became an affiliate member of the EPA SmartWay Program. SmartWay is a public-private initiative involving state and federal agencies, trucking and rail carriers, manufacturers, retailers, and others to improve fuel efficiency and reduce air pollution.

Working through the state’s idling working group, DNREC is helping add local commercial partners and affiliates to the program.

Mid-Atlantic Diesel Collaborative

Delaware participates in Mid-Atlantic Region Air Management Association (MARAMA) Alternative Power Unit grant program, which provides funds to small business trucking companies to purchase alternative power units and is a part of the Mid-Atlantic Diesel Collaborative, a regional partnership to reduce diesel emissions.




+