Anti-idling initiatives include organizational policies and awareness campaigns to minimize the time that drivers idle the engines of their personal or fleet vehicles. These efforts are often implemented in support of federal, state, or local anti-idling laws but can also be standalone efforts by neighborhoods or near schools. Anti-idling campaigns typically include education efforts, anti-idling signs in loading/unloading zones, and pledges to change behavior. Initiatives can promote use of idle reduction technologies for buses or trucks such as auxiliary power units (APUs), automatic shutdown/start-up devices, or battery-powered air conditioning1. When idling, gasoline- and diesel-powered engines consume fuel and produce greenhouse gas emissions and hydrocarbons that can react to form smog and emit pollutants such as nitrogen oxides (NOx), particulate matter, and toxic air pollutants that negatively affect cardiovascular and respiratory health, especially for children, and contribute to climate change2, 3, 4.
Expected Beneficial Outcomes (Rated)
Reduced vehicle idling
Other Potential Beneficial Outcomes
Improved air quality
Improved health outcomes
Evidence of Effectiveness
There is some evidence that anti-idling initiatives reduce vehicle idling time and emissions, and improve air quality, especially near schools with high levels of traffic5, 6, 7, 8. Research shows that idling school buses increase children’s exposure to air pollutants in the school vicinity9, 10, 11, 12. Vehicles that are turned off do not use fuel or emit the air pollutants and greenhouse gases emitted when idling. Several idle reduction technologies have been shown to significantly reduce fuel use and emissions of pollutants such as NOx, PM, and CO21, 13, 14. However, additional evidence is needed to confirm the effects of anti-idling initiatives on idling levels.
An evaluation of a Georgia school district’s anti-idling program that used an on-board idle detection and warning system suggests such programs can reduce idle times, save fuel, and reduce emissions7. A Cincinnati-based effort indicates that anti-idling campaigns near schools with many buses and high levels of traffic can also improve indoor air quality by reducing traffic aerosols6. Surveys suggest that community and driver knowledge of the health benefits of reducing idling increase with anti-idling education efforts15.
Research suggests that successful anti-idling policies establish a baseline, educate drivers, gather and analyze data, set goals, have a written policy, and measure and report success8. Pairing idle reduction technologies for buses and trucks with anti-idling policies can increase reductions in emissions1.
Idle reduction initiatives are a low cost way to reduce idling and emissions and to save fuel8. Several idle reduction technologies have been shown to be cost-effective with payback times of half a year or less. For example, installing an auxiliary power unit (APU) costs approximately $8,000 per bus with an annual savings of $12,400-$14,700, and automatic shutdown/start-up devices cost $1,200 per bus, with an annual savings of $11,700-$14,400. Battery-powered air conditioning and diesel-fired heaters cost $7,500 per bus, with an annual savings of $13,800-$14,7001.
Impact on Disparities
As of 2017, 27 states and Washington DC have laws or regulations that address idling; 36 states have state-wide incentives16. Philadelphia’s Idle Free Philly campaign, which also uses a mobile app and website to facilitate reports of idling vehicles and support enforcement, is an example of a campaign to raise awareness of state and municipal law17. New Jersey’s state anti-idling law applies to heavy duty trucks and passenger vehicles, and is supported by a Stop the Soot campaign that encourages pledges to reduce school bus idling18, 19.
Many municipalities support anti-idling efforts; for example, San Antonio passed an anti-idling ordinance for heavy duty trucks with a 5 minute idling limit, effective in January 201720, and Park City, Utah prohibits vehicle idling for more than 1 minute21. Municipalities and business owners can install electrified parking spaces at truck stops, rest areas, and distribution centers to provide power, heating, and cooling to the cab without idling; however, these efforts are not yet widespread22.
Several federal programs support reductions in emissions through idle reduction efforts, such as the Congestion Mitigation and Air Quality (CMAQ) Improvement Program, Clean Cities, Clean School Bus USA, and the SmartWay Transport Partnership. The federal government also offers an idle reduction equipment excise tax exemption and an idle reduction technology weight exemption. The federal weight exemption allows states to permit heavy duty vehicles equipped with idle reduction technology to exceed the maximum gross vehicle weight limit and axle weight limit to compensate for the additional weight of idle reduction technology without affecting state highway funding eligibility23.
US DOE-AFDC idle reduction - US Department of Energy (US DOE), Energy Efficiency & Renewable Energy (EERE). Alternative Fuels Data Center (AFDC): Idle reduction.
US DOE-VTO idle reduction - US Department of Energy (US DOE), Energy Efficiency & Renewable Energy (EERE). Vehicle Technologies Office (VTO): Idle reduction research and resources.
US DOE-IdleBox toolkit - US Department of Energy (US DOE), Energy Efficiency & Renewable Energy (EERE). Clean cities: IdleBox toolkit for idling reduction projects.
NRC-Idle free - Natural Resources Canada (NRC). Idle free zone resources for communities and government.
US EPA-Idle free schools - US Environmental Protection Agency (US EPA). Region 8: Idle free schools toolkit and resources.
US EPA-SmartWay - US Environmental Protection Agency (US EPA). SmartWay.
US DOT-Idle reduction - US Department of Transportation (US DOT). Congestion mitigation and air quality improvement (CMAQ) program: Idle reduction techniques.
ChangeLab-No idling - ChangeLab Solutions. No idling policy.
* Journal subscription may be required for access.
1 Ziring 2010* - Ziring E, Sriraj PS. Mitigating excessive idling of transit buses. Transportation Research Record: Journal of the Transportation Research Board. 2010;2143:142-149.
2 NH DES-Motor vehicles - New Hampshire Department of Environmental Services (NH DES). Motor vehicles and toxic air pollutants.
3 CDC-Clean diesel - Centers for Disease Control and Prevention (CDC), Office of the Associate Director for Policy and Strategy. Clean diesel bus fleets. Health impact in 5 years (HI-5): Transitioning bus fleets, cleaner air for a healthier community.
4 US EPA-Idle free schools - US Environmental Protection Agency (US EPA). Region 8: Idle free schools toolkit and resources.
5 Ryan 2013* - Ryan PH, Reponen T, Simmons M, et al. The impact of an anti-idling campaign on outdoor air quality at four urban schools. Environmental Science: Processes & Impacts. 2013;15(11):2030-2037.
6 Kim 2014 - Kim JY, Ryan PH, Yermakov M, et al. The effect of an anti-idling campaign on indoor aerosol at urban schools. Aerosol and Air Quality Research. 2014;14:585-595.
7 Xu 2013a* - Xu Y, Elango V, Guensler R, Khoeini S. Idle monitoring, real-time intervention, and emission reductions from Cobb County, Georgia, school buses. Transportation Research Record: Journal of the Transportation Research Board. 2013;2340:59-65.
8 Anderson 2009a - Anderson Y, Glencross CC. School bus idling reduction: Project report & implementation guide for Oklahoma school districts. Oklahoma City, OK: Association of Central Oklahoma Governments; 2009.
9 Zhu 2014 - Zhu Y, Zhang Q. Characterizing ultrafine particles and other air pollutants in and around school buses. Boston, MA: Health Effects Institute (HEI); 2014.
10 Zhang 2013* - Zhang Q, Fischer HJ, Weiss RE, Zhu Y. Ultrafine particle concentrations in and around idling school buses. Atmospheric Environment. 2013;69(2):65-75.
11 Hochstetler 2011 - Hochstetler HA, Yermakov M, Reponen T, Ryan PH, Grinshpun SA. Aerosol particles generated by diesel-powered school buses at urban schools as a source of children’s exposure. Atmospheric Environment. 2011;45(7):1444-1453.
12 Li 2009* - Li C, Nguyen Q, Ryan PH, et al. School bus pollution and changes in the air quality at schools: A case study. Journal of Environmental Monitoring. 2009;11(5):1037-1042.
13 US DOE-AFDC research - US Department of Energy (US DOE), Energy Efficiency & Renewable Energy (EERE). Alternative Fuels Data Center (AFDC): Idle reduction research and development.
14 NREL-Proc 2003 - Proc K, Nitschke B, Wagner F, et al. Idle reduction technology demonstration plan: Update. National Renewable Energy Laboratory (NREL). 2003.
15 Eghbalnia 2013* - Eghbalnia C, Sharkey K, Garland-Porter D, et al. A community-based participatory research partnership to reduce vehicle idling near public schools. Journal of Environmental Health. 2013;75(9):14-19.
16 US DOE-AFDC laws and incentives - US Department of Energy (US DOE), Energy Efficiency & Renewable Energy (EERE). Alternative Fuels Data Center (AFDC): Search federal and state laws and incentives.
17 CAC-Idle free Philly - Clean Air Council (CAC). Idle free Philly.
18 NJ DEP-Idling restrictions - State of New Jersey Department of Environmental Protection (NJ DEP), Bureau of Mobile Sources. Idling restrictions.
19 NJ DEP-School bus - State of New Jersey Department of Environmental Protection (NJ DEP), Bureau of Mobile Sources. School bus idling.
20 San Antonio-Anti-idling - City of San Antonio. Anti-idling ordinance.
21 Park City-Anti-idling - Park City, Utah. Anti-idling ordinance.
22 Trucking Efficiency - Trucking Efficiency. Truck stop electrification.
23 US DOE-AFDC Federal laws - US Department of Energy (US DOE), Energy Efficiency & Renewable Energy (EERE). Alternative Fuels Data Center (AFDC): Federal laws and incentives for idle reduction.
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