TABLE 6-1 Comparison of Attributes of Idle Reduction Systems

Idle Reduction Technology Heating Cooling Electric Requires Recharge Infrastructure Service Fee Emissions Control Needed? Idle Time Avoided per Year Fuel Use (gal/hr) % Benefit Cost
Engine Control Yes Yes Yes No No No 1,500 to 2,400 ~0.5 3% $1,000 to $4,000
Heater Yes No No No No No 500 to 800 0.2 to 0.3 1.3 to 2.3% $1,000 to $3,000
Auxiliary Power Unit Yes Yes Yes No No In California 1,500 to 2,400 0.2 to 0.3 4 to 7% $6,000 to $8,000
Battery Yes Yes Some Yes No No 1,500 to 2,400 5 to 9% $3,000 to $8,000a
Shore power Yes Yes Yes Yes Yes Yes 1,500 to 2,400 5 to 9% ~$100


image Green: Favorable Attribute
Yellow: Mild Drawback
Dark Orange: Major Drawback

a May require a diesel particulate filter, at an additional cost of $3,000.

SOURCE: NRC (2010), Table 5-24, p. 125.

anti-idling regulations more aggressively (DOE, 2011; Delphi, 2010). The California Air Resources Board (CARB) adopted a rule that since 2007 has not only limited idling to 5 minutes, but also requires automatic shutoff devices. Philadelphia bans the idling of heavy-duty diesel-powered motor vehicles, with exceptions made during cold weather.


The NRC Phase 1 report did not contain a breakdown of the 21CTP budget for idle reduction through 2008 (NRC, 2008). Likewise, the 21CTP budget for idle reduction efforts was not available for FY 2009 and FY 2010 and the FY 2011 President’s Congressional Budget Request (see Table 1-2 in Chapter 1 of this report). Similarly, a budget forecast for meeting the idle reduction goals that extend through 2017 to reduce fuel use and emissions produced by idling engines was not provided to the committee. Therefore, an assessment of the probability of achieving the goals for idle reduction technologies cannot be made at this time. However, as noted in the section, “Goals,” the American Recovery and Reinvestment Act (ARRA) of 2009 did provide funds for idle-reduction related projects.


In the NRC Phase 1 report, seven 21CTP goals for engine idle reduction were addressed (NRC, 2008). In its November 15, 2010, presentation to the committee, the 21CTP slightly modified these goals for 2010 and added one new goal. Those goals are presented in bold type in this section. The action items addressing these goals provide a path toward accomplishing the overall goal of the idle reduction portion of the 21CTP. The status of action items addressing each of these goals is discussed in this section.

21CTP Engine Idle Reduction Goal 1. Continue industry/government collaboration to promote the development and deployment of cost-effective technologies for reducing fuel use and emissions due to idling of heavy-duty engines.

For more than a decade, the Department of Energy (DOE) has carried out cooperative research and development (R&D) to characterize and address the reduction of fuel use and emissions during the idling of heavy-duty engines. The NRC (2008) Phase 1 report discussed the R&D work focused on idling reduction technologies. All of the 21CTP partners, both government and industry, have ongoing roles in developing and implementing a coherent program of idling reduction, as described below:

   The DOE analyzes technology needs and performs the appropriate R&D to help make cost-effective technology available for implementation. The results of the analyses enable a systematic comparison of potential strategies, including emission credits, positive incentives, and regulations to install appropriate idle reduction technology.

   The Environmental Protection Agency (EPA) and the Department of Transportation (DOT) have been named to lead the effort in implementation.

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