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National Clean Diesel Campaign (NCDC)

Working Together for Cleaner Air

Operations & Idle Reduction

Idle reduction and operational strategies reduce emissions by maximizing efficient use of equipment and limiting the amount of time an engine needs to operate.

Idle Reduction

Aftermarket auxiliary heaters can be used to warm engines and passenger compartments in colder climates. These heaters run off diesel fuel or electric outlets and include a programmable timer to automatically start or stop the heating function. There are three types of heaters:

  • Fuel-Operated Engine Block Heaters are used to heat the engine block for a warm start. Each block pre-heater uses only half a cup of diesel fuel per hour compared to half a gallon or more of fuel per hour while idling. Benefits of these heaters are fuel savings, lower emissions, longer engine oil life, less wear-and-tear on the engine, and relatively easy installation and maintenance. They can be used in areas where electrical block heaters are not feasible and can be started by a timer.
  • Electric Plug-in Block Heaters warm the engine block by heating the engine coolant or oil. They are powered by electricity and are available in a range of voltages and watts, drawing between 1000 - 1500 watts per bus per hour. A heater is mounted on the engine block and is plugged in when the bus is parked at the depot. Even in the coldest climates, engines will have a "warm start." The heater includes a timer that automatically turns it on or off. Bus depots and garages can be designed or retrofitted to bring in the electrical service required.
  • Compartment and Engine Block Heaters warm the engine block and passenger compartment simultaneously using an auxiliary heater. These heaters use only one cup of fuel per hour compared to half a gallon of fuel needed to idle for an hour. They are especially useful for nighttime-activity buses and buses that transport very young and/or special-needs children. In addition, the radiant heat improves safety by preventing the windows from frosting or fogging.

Learn more about idle reduction technologies.

Operational Strategies

Operational strategies will likely be unique for each situation and should be reviewed periodically. The benefits of operational strategies will differ depending on the original procedures and the degree of change implemented. Although operational strategies are not part of the NCDC verification process, they are important for overall emission reductions and cost savings can be substantial.


Operational Efficiencies save fuel and prevent unnecessary wear on engines.

  • Gate efficiencies such as parking trucks to wait for loading instead of idling in long lines
  • Web-based appointment systems or reservation system for trucks
  • Expanded hours or incentives for off-peak operation to avoid lines
  • Electric shore side power at berth in place of operating auxiliary diesel engines (cold ironing)
  • Electric dredging and electric cranes
  • Multi-Tillage, such as applying nutrients and pesticides at the same time

Improved Container Management reduces emissions and congestion.

  • Better tracking of containers – where the empties are and who needs them
  • Improved stacking practices
  • Homeland security changes
  • Direct intermodal transfers (i.e., cargo transferred directly from ship to rail)

More Efficient Freight Movement reduces emissions and congestion.

  • Barge or rail transport of cargo in place of trucking

Marine Vessel Speed Limits can reduce emissions as emissions typically increase with speed.

  • Typically limited to a certain distance from the port

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