Noise Sources

People boarding a shuttle bus on the rim of the Grand Canyon.
Grand Canyon National Park uses a shuttle bus system to reduce vehicle congestion along certain parts of the rim road.

NPS Photo


  • Cars, motorcycles and other motor vehicles are the most pervasive noise source in parks that:
    • may cause delays and backups which detract from the visitor experience;
    • negatively impact wildlife through collisions, habitat fragmentation, and noise; and
    • contribute to air pollution.
  • Many parks offer alternative transportation, such as shuttles.
  • Energy-efficient hybrid and electric vehicles are quieter than gas-powered vehicles.
NPS conducts education efforts targeting drivers of loud vehicles.
Helicopter and Statue of Liberty
A Park Police helicopter in front of the Statue of Liberty.

NPS Photo by Zeph Cunningham


  • Air tours, general aviation, commercial flights, military flights, fire and emergency flights, and scientific and maintenance flights may occur over parks.
  • Air tours offer a unique perspective on national parks and are increasing in popularity but may impact visitors and wildlife on the ground.
  • With the National Parks Air Tour Management Act (NPATMA), Congress mandated the Federal. Aviation Administration (FAA) and the National Park Service to work together to mitigate or prevent adverse impacts to park resources and values from commercial air tours.
  • The NPS collaborates with the U.S. Military to balance needs for military training flights and protection of park resources and visitor experiences.
  • An outstanding example of a cooperative relationship between the NPS and USAF, the jointly developed military sourcebook helps both agencies better address military overflights.
  • Expansion of small regional airports has the potential to impact many parks.
Person on a snowmobile in a winter landscape.
Snowmobiles are allowed in some national parks.

NPS Photo

Snowmobiles & Off-Road Vehicles

  • Snowmobiles have been a topic of debate in Yellowstone National Park for many years.
  • Noise, air, and water pollution and impacts to wildlife were all cited as reasons to manage snowmobiles.
  • Since enacting regulations, Yellowstone staff has measured some of the quietest conditions they have ever recorded in the natural environment. Learn more about Yellowstone's Winter Use.
  • Off-road vehicles (ORVs) also pose concerns including noise, air, and water pollution, erosion, and impacts to wildlife.
  • Acoustical data can play a role in creating policies to manage ORVs.
  • Noise modeling helps park managers better understand how and where noise travels.

A snowplow blows snow off of a road.
A snowplow clears Rim Road at Crater Lake National Park.

NPS Photo

Park Operations

  • Snow plows, construction, grounds care, buildings, and aircraft are among the sources of noise that may come from park operations.
  • Some noise is unavoidable, but NPS management policies require parks to "monitor mechanical noise that adversely affects opportunities to enjoy park soundscapes."
  • Parks may choose quieter tools for a job when possible (for example, a handsaw in place of a chainsaw in wilderness areas).
  • Noisy equipment may be relocated away from sensitive areas.
  • Loud activities may be scheduled at times when they will have the least impact.
  • Generators may be replaced or supplemented by batteries or solar power.
  • Quieter motorized tools and vehicles are often more energy-efficient, making them a great choice for parks concerned about emissions.
A woman on a personal watercraft on a lake with desert landscape in the background.
Personal watercraft are often seen at Lake Mead National Recreation Area, though they are banned in some other national parks.

NPS Photo by Christie Vanover


  • NPS has determined that personal watercraft (PWC) use can "have a direct and adverse effect on park values such as peace and quiet."
  • In April 2000, PWC use was banned in national parks except where it is consistent with the unit's enabling legislation or overall management objectives.
  • As with snowmobiles, ORVs, and other forms of motorized recreation, measuring noise levels of PWCs has helped park managers evaluate impacts and make informed decisions.
  • NPS continues to collect acoustical data and model potential noise impacts to provide guidance for this on-going issue.
Drill rig in scrubland environment.
Energy development can impact both the landscape and the acoustic environment of a national park.

Photo by Graeme Shannon

Energy Development

  • Oil and gas development near parks can have a great impact on the acoustic environment, including not only the drilling itself but also the infrastructure and transportation that comes with it.
  • Renewable energy, including geothermal, hydropower, wind, and solar, provide many benefits to the natural environment.
  • Renewable energy development still impacts the environment, including the acoustic environment.
  • The National Park Service works to minimize or mitigate impacts of all types of energy development.
  • Acoustical data and modeling are critical to understanding impacts of energy development.
  • Close coordination between park management, cooperating agencies, and commercial interests is required to ensure that energy development is compatible with protection of park resources and visitor enjoyment.