Examples of environmental issues or resources that could be affected by major transit projects include: social and economic impacts; air quality; endangered species; environmental justice; floodplains; hazardous materials and Brownfields; historic, archeological, and cultural resources; noise and vibration; parklands; transportation impacts; water quality; and wetlands. Although the primary concern of NEPA studies is adverse impacts, some resources may be affected beneficially by transit projects. Often, transit improvements can have positive impacts on land use, economic development, environmental justice, air quality, transportation, and other resources.

Although potential effects on all known environmental resources in the study area will be seriously considered and studied, a few that may require close attention include the following:

Noise and vibration: All motorized vehicles generate noise, so any proposal for new transit operations must include consideration of potential noise impacts from passing transit vehicles. Many large transit vehicles also generate vibrations that may affect nearby residences and businesses. These impacts may not be significant, but if they are, measures to minimize or mitigate them will be evaluated for inclusion in the project.

Cultural resources: Central Austin has many buildings and structures of historic age (50 years or more) and any transit circulator system is likely to run near some of them. Properties on or eligible for the National Register of Historic Places are protected under the National Historic Preservation Act and the Department of Transportation Act. Identification of such sites within the project’s area of potential effect and determination of potential impacts, if any, will be part of the EA process.

Environmental justice: Federal law requires that federally-assisted projects do not cause disproportionately high and adverse environmental impacts on minority and low-income populations. To ensure this principle of environmental justice, potential impacts are scrutinized for disproportionate effect during the EA process. Central Austin has substantial numbers of Hispanic/Latino, African-American, Asian, and low-income residents. Potential effects on these populations are likely also to include benefits from improved public transportation services.

Aesthetics and visual quality: The increased presence of transit vehicles and, possibly, stationary facilities supporting their operation may alter the streetscape where improvements are made. Potential changes in the streetscape could include more street-level transit vehicles stopping for passengers, new bus stops or rail platforms, overhead caternaries and wires to power streetcars or trolley buses, or elevated track structures and support columns for a monorail system.