Vehicle anti-idling initiatives
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, particulate matter, and toxic air pollutants that negatively affect cardiovascular and respiratory health, especially for children, and contribute to climate change2, 3.
What could this strategy improve?
Expected Benefits
Our evidence rating is based on the likelihood of achieving these outcomes:
Reduced vehicle idling
Potential Benefits
Our evidence rating is not based on these outcomes, but these benefits may also be possible:
Reduced emissions
Improved air quality
Improved health outcomes
What does the research say about 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 traffic4, 5, 6, 7, 8, 9. Research shows that idling school buses increase children’s exposure to air pollutants in the school vicinity10, 11, 12, 13. 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 nitrogen oxides, particulate matter, and carbon dioxide1, 14, 15. 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 emissions8. 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 aerosols7. A short anti-idling campaign focused on school drop-off zones in Salt Lake City, Utah, appeared to modestly improve air quality and to reduce the time and number of vehicles observed idling4. An Australian study also finds a 4-week, low-intensity intervention with parents improves air quality and reduces idling near schools5. Surveys suggest that community and driver knowledge of the health benefits of reducing idling increases with anti-idling education efforts16.
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 success9. Planners should also consider local weather and regional climate variability in designing initiatives and measuring effects4. Experts also recommend prioritizing anti-idling policies and incentives to reduce using gas- and diesel-powered vehicles, over strategies which reduce emissions’ effects, such as vegetation barriers17.
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 fuel9. Several idle reduction technologies have been shown to be cost-effective with payback times of half a year or less1. Experts suggest that educational campaigns may change idling behavior among some drivers of personal vehicles, but that technology-based solutions with education may be most effective at reducing idling, especially when vehicle power is needed for occupational purposes (e.g. long-haul trucking, police and ambulance fleets, school buses)18.
Idling is estimated to waste six billion gallons of fuel annually, with personal vehicles accounting for three billion gallons and generating 30 million tons of CO2. Stopping unnecessary idling of personal vehicles equates to taking five million vehicles off the road19.
How could this strategy advance health equity? This strategy is rated potential to decrease disparities: suggested by expert opinion.
Efforts to reduce exhaust emissions – including through reduced vehicle idling – have the potential to decrease existing disparities in air pollution exposure rates by race, ethnicity, and income26, 27, 28. Anti-idling campaigns can reduce idling time and emissions, and improve air quality4, 5, 6, 7, 8, 9, and idle reduction technologies significantly reduce fuel use and pollutant emissions1, 14, 15. Available evidence suggests that racial disparities in air pollution exposure have declined, although racial disparities persist27. Experts suggest programs should identify neighborhoods where emissions reductions can reduce average exposure, exposure inequality, and exposure injustice as well as account for meteorology and the movement of air pollution to reduce disparities in exposure28.
Higher exposure to air pollution and toxic emissions has been associated with disparities in health outcomes between people of color and people with low incomes and white people and people with higher incomes26. Air pollution exposure and living in neighborhoods with heavy traffic is associated with many adverse health effects, including asthma, respiratory disease, cardiovascular disease, cancers, adverse birth outcomes, cognitive decline, dementia, and more27, 29. Children living near heavy traffic are more likely to have asthma than children living in neighborhoods without traffic; children of color are also more likely to have or develop asthma than white children29. Other studies suggest more Black individuals are diagnosed with and hospitalized for asthma, compared with white individuals30.
Individuals living nearer to bus depots are exposed to toxic emissions from large numbers of idling buses. Existing research suggests that cleaner transportation options, like commuter rail, tend to be more accessible to wealthier communities, while buses are more accessible to communities with lower incomes and more individuals of color. A study of New York City finds that census tracts with higher percentages of Hispanic or Black individuals tend to be closer to bus depots in most boroughs and suggests that belonging to a marginalized racial group may contribute to pollution exposure, in some cases regardless of socio-economic status. An analysis estimates that transitioning New York City’s bus fleet to electric buses would save $150,000 per bus through reductions in hospitalizations, emergency room costs, and missed work, and experts suggest that initiatives addressing air pollution from buses could reduce disparities in lung-related illness and financial burden among Black individuals. Experts recommend that planners consider race and class disparities when deciding where to focus efforts to reduce idling and where to test and implement cleaner technologies30.
What is the relevant historical background?
Throughout U.S. history, discriminatory housing, lending, and exclusionary zoning policies entrenched racial residential segregation and concentrated poverty31, 32. Many urban areas in the U.S. experienced unrestrained industrialization without environmental regulations or land use controls creating environmental problems, including water and air pollution, waste production, overconsumption of natural resources, and loss of green space33. Early U.S. environmental movements focused on conservation and nature preservation and did not consider urban environmental inequities or public health34. The built environment in under-resourced communities is a significant contributor to health inequities for people of color with low incomes35, 36, 37. Formerly redlined neighborhoods remain more likely to include vacant lots and blighted properties, older homes in poor condition, coal-fired power plants, hazardous waste disposal sites, and other health risks38. Communities with low incomes and communities of color still have fewer places to engage in outdoor activities, have less access to cooling shade, experience more extreme heat, and experience poorer air quality39, 40, 41.
The Air Pollution Control Act of 1955 was the first federal legislation to identify and provide funds for air pollution research. The Clean Air Act of 1963 began the process of air pollution control, and many iterations of the legislation followed. Notably, the Clean Air Act of 1970 authorized the U.S. Environmental Protection Agency (EPA) to establish, regulate, monitor, and enforce National Ambient Air Quality Standards to protect public health from widespread hazardous air pollutants, especially particulate matter, ozone, sulfur dioxide, nitrogen dioxide, carbon monoxide, and lead. This legislation regulates and enforces reductions of many types of air pollution from multiple pollution sources, including motor vehicles. The 1990 Clean Air Act Amendments established updated goals and technology standards to reduce hazardous air pollution42, 43, 44. The federal Clean Air Act has reduced disparities in hazardous pollutant exposure, although racial disparities continue to persist45. EPA standards for cleaner vehicles and fuel aim to reduce pollutants which harm human health and the environment, as emissions from personal and commercial vehicles, and their fuel, continue to be a large source of pollution exposure46.
Environmental justice groups, such as West Harlem Environment Action (WE ACT) in New York City, have campaigned for equitable siting of bus depots and for cities to invest in cleaner buses, since the 1980s. These groups have also partnered with academic researchers to study health risks associated with New York City’s transit systems. Some cities have had anti-idling laws since the 1970s but enforcing the laws remains difficult. In 2015, New York City began offering financial incentives for citizens to report idling through its Air Complaint Program30.
Equity Considerations
- What neighborhoods in your community suffer from poor air quality and high levels of pollutant exposures?
- What anti-idling laws or ordinances are in place in your community and state? How are they enforced? How are the laws’ effects measured?
- Who is leading local efforts to reduce emissions from idling? Are there efforts in multiple sectors (e.g., transportation, tourism) to reduce idling and disproportionate exposure to air pollution (e.g., by occupation, neighborhood)?
- Is there investment locally in strategies which stop idling altogether, including alternatives to vehicle use (e.g., improving bike and pedestrian routes)?
Implementation Examples
As of 2023, 28 states and Washington, D.C. have laws or regulations that address idling; 38 states have state-wide incentives20. New Jersey’s state anti-idling law applies to heavy duty trucks and passenger vehicles and is supported by a Stop the Soot campaign21.
Many municipalities support anti-idling efforts; for example, San Antonio passed an anti-idling ordinance for heavy duty trucks with a five minute idling limit, effective in January 201722, and Park City, Utah prohibits vehicle idling for more than one minute23. 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 widespread24.
Several federal programs support reductions in emissions through idle reduction efforts, such as the Congestion Mitigation and Air Quality (CMAQ) Improvement Program, Clean Cities Coalition Network, 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 eligibility25.
Implementation Resources
‡ Resources with a focus on equity.
US DOE-AFDC idle reduction - U.S. Department of Energy (U.S. DOE), Energy Efficiency & Renewable Energy (EERE). Alternative Fuels Data Center (AFDC): Idle reduction.
US DOE-VTO idle reduction - U.S. Department of Energy (U.S. DOE), Energy Efficiency & Renewable Energy (EERE). Vehicle Technologies Office (VTO): Idle reduction research and resources.
US DOE-IdleBox toolkit - U.S. Department of Energy (U.S. 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 - U.S. Environmental Protection Agency (U.S. EPA). Region 8: Idle free schools toolkit and resources.
US EPA-SmartWay - U.S. Environmental Protection Agency (U.S. EPA). SmartWay.
US DOT-Idle reduction - U.S. Department of Transportation (U.S. DOT). Congestion mitigation and air quality improvement (CMAQ) program: Idle reduction techniques.
World Emissions Clock - World Data Lab. World Emissions Clock.
Footnotes
* 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 CDC-Cleaner fleets - Centers for Disease Control and Prevention (CDC), Office of the Associate Director for Policy and Strategy. Cleaner and alternative bus fleets. Health impact in 5 years (HI-5): Transitioning bus fleets, cleaner air for a healthier community.
3 US EPA-Idle free schools - U.S. Environmental Protection Agency (U.S. EPA). Region 8: Idle free schools toolkit and resources.
4 Mendoza 2022 - Mendoza DL, Benney TM, Bares R, et al. Air quality and behavioral impacts of anti-idling campaigns in school drop-off zones. Atmosphere. 2022;13(706):1-19.
5 Rumchev 2020 - Rumchev K, Lee A, Maycock B, Jancey J. Reducing car idling at primary schools: An intervention study of parent behaviour change in Perth, Western Australia. Health Promotion Journal of Australia. 2021;32(3):383-390.
6 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.
7 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.
8 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.
9 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.
10 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.
11 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.
12 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.
13 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.
14 US DOE-AFDC research - U.S. Department of Energy (U.S. DOE), Energy Efficiency & Renewable Energy (EERE). Alternative Fuels Data Center (AFDC): Idle reduction research and development.
15 NREL-Proc 2003 - Proc K, Nitschke B, Wagner F, et al. Idle reduction technology demonstration plan: Update. National Renewable Energy Laboratory (NREL). 2003.
16 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.
17 GCCAR-Kumar 2020 - Kumar P, Omidvarborna H, Barwise Y, Tiwari A. Mitigating exposure to traffic pollution in and around schools: Guidance for children, schools and local communities. Global Centre for Clean Air Research (GCCAR), University of Surrey; 2020.
18 U.S. DOE-Gaines 2015 - Gaines L, Weikersheimer P. Status and issues for idling reduction in the United States: Alternative fuel and advanced vehicle technology market trends. Lemont, IL: Argonne National Laboratory; U.S. Department of Energy (U.S. DOE); 2015.
19 U.S. DOE-Idling reduction - U.S. Department of Energy (U.S. DOE), Argonne National Laboratory, Vehicle Technologies Office. Idling reduction for personal vehicles. 2015.
20 US DOE-AFDC laws and incentives - U.S. Department of Energy (U.S. DOE), Energy Efficiency & Renewable Energy (EERE). Alternative Fuels Data Center (AFDC): Search federal and state laws and incentives.
21 NJ DEP-Idling restrictions - State of New Jersey Department of Environmental Protection (NJ DEP), Bureau of Mobile Sources. Idling restrictions.
22 San Antonio-Anti-idling - City of San Antonio. Anti-idling ordinance.
23 Park City-Anti-idling - Park City, Utah. Anti-idling ordinance.
24 Trucking Efficiency - Trucking Efficiency. Truck stop electrification.
25 US DOE-AFDC Federal laws - U.S. Department of Energy (U.S. DOE), Energy Efficiency & Renewable Energy (EERE). Alternative Fuels Data Center (AFDC): Federal laws and incentives for idle reduction.
26 Demetillo 2021 - Demetillo MAG, Harkins C, McDonald BC, et al. Space-based observational constraints on NO2 air pollution inequality from diesel traffic in major U.S. cities. Geophysical Research Letters. 2021;48(17).
27 Liu 2021 - Liu J, Clark LP, Bechle MJ, et al. Disparities in air pollution exposure in the United States by race/ethnicity and income, 1990-2010. Environmental Health Perspectives. 2021;129(12):1-14.
28 Nguyen 2018 - Nguyen NP, Marshall JD. Impact, efficiency, inequality, and injustice of urban air pollution: Variability by emission location. Environmental Research Letters. 2018;13.
29 Commodore 2021 - Commodore S, Ferguson PL, Neelon B, et al. Reported neighborhood traffic and the odds of asthma/asthma-like symptoms: A cross-sectional analysis of a multi-racial cohort of children. International Journal of Environmental Research and Public Health. 2021;18(1):1-25.
30 McKane 2018 - McKane RG, Satcher LA, Houston SL, Hess DJ. Race, class, and space: An intersectional approach to environmental justice in New York City. Environmental Sociology. 2018;4(1):79-92.
31 Zdenek 2017 - Zdenek RO, Walsh D. Navigating community development: Harnessing comparative advantages to create strategic partnerships. Chapter: The background and history of community development organizations. New York: Palgrave Macmillan; 2017.
32 Kaplan 2007 - Kaplan J, Valls A. Housing discrimination as a basis for Black reparations. Public Affairs Quarterly. 2007;21(3):255-273.
33 Lampert 2021 - Lampert T, Costa J, Santos O, et al. Evidence on the contribution of community gardens to promote physical and mental health and well-being of non-institutionalized individuals: A systematic review. PLOS ONE. 2021;16(8):e0255621.
34 NEJAC 2006 - The National Environmental Justice Advisory Council (NEJAC). Unintended impacts of redevelopment and revitalization efforts in five environmental justice communities. 2006.
35 Prochnow 2022 - Prochnow T, Valdez D, Curran LS, et al. Multifaceted scoping review of Black/African American transportation and land use expert recommendations on activity-friendly routes to everyday destinations. Health Promotion Practice. 2022.
36 McAndrews 2022 - McAndrews C, Schneider RJ, Yang Y, et al. Toward a gender-inclusive Complete Streets movement. Journal of Planning Literature. 2022;38(1):3-18.
37 Brookings-Semmelroth 2020 - Semmelroth L. How Wilmington, Del. is revitalizing vacant land to rebuild community trust. Washington, D.C.: Brookings Institution; 2020.
38 Braveman 2022 - Braveman PA, Arkin E, Proctor D, Kauh T, Holm N. Systemic and structural racism: Definitions, examples, health damages, and approaches to dismantling. Health Affairs. 2022;41(2):171-178.
39 KFF-Ndugga 2022 - Ndugga N, Artiga S. Climate change and health equity: Key questions and answers. KFF. May 24, 2022.
40 CAP-Rowland-Shea 2020 - Rowland-Shea J, Doshi S, Edberg S, Fanger R. The nature gap: Confronting racial and economic disparities in the destruction and protection of nature in America. Washington, D.C.: Center for American Progress (CAP); 2020.
41 TPL-Chapman 2021 - Chapman R, Foderaro L, Hwang L, et al. Parks and an equitable recovery. San Francisco, CA: The Trust for Public Land (TPL); 2021.
42 US EPA-Evolving federal legislation - U.S. Environmental Protection Agency (U.S. EPA). Evolution of the Clean Air Act.
43 US EPA-CAA History - U.S. Environmental Protection Agency (U.S. EPA). Clean Air Act (CAA) requirements and history.
44 US EPA-CAA - U.S. Environmental Protection Agency (U.S. EPA). Summary of the Clean Air Act.
45 NBER-Currie 2021 - Currie J, Voorheis J, Walker R. What caused racial disparities in particulate exposure to fall? New evidence from the Clean Air Act and satellite-based measures of air quality. National Bureau of Economic Research (NBER). 2021: Working Paper 26659.
46 US EPA-Air pollution challenges - U.S. Environmental Protection Agency (U.S. EPA). Air pollution: Current and future challenges.
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