Environmental Guidance

NEPA Guidance for Federal Aid Projects

Federal-Aid Highway Act

The Federal-Aid Highway Act of 1972 requires FHWA to develop a noise standard for new federal-aid highway projects. The standard provides national criteria for all highway agencies but also gives state DOTs flexibility in managing highway traffic and construction noise. In addition to defining traffic noise impacts, the FHWA Noise Standard requires that noise abatement be considered when traffic noise levels that exceed a defined threshold are identified during noise analysis, planning and project design.

EPG provides technical expertise to evaluate noise impacts that may result from ADOT transportation projects. Specialized noise modeling is used for projects that increase traffic capacity or that have changes in the vertical and/or horizontal alignment of a roadway project.

Noise Abatement

FHWA regulations for noise evaluation are detailed in Title 23 CFR 772, Procedures for Abatement of Highway Traffic Noise and Construction Noise. The main objectives of 23 CFR 772 are "to provide procedures for noise studies and noise abatement measures, to help protect the public health and welfare, to supply noise abatement criteria, and to establish requirements for information to be given to local officials for use in the planning and design of highways approved pursuant to Title 23, United States Code (U.S.C.)." The regulations require the consideration of noise abatement mitigation when traffic noise impacts that exceed a defined threshold are identified.

The FHWA regulations require the following during the planning and design of a highway project:

  • Identification of traffic noise impacts and examination of potential mitigation measures
  • Incorporation of reasonable (resident/owner preferences, noise reduction goals, cost effectiveness) and feasible (engineering and acoustic) noise mitigation measures into the highway project
  • Coordination with local officials to provide helpful information on compatible land use planning and control
NEPA Process

If traffic noise impacts are expected and sensitive receivers are present, the effects must be disclosed under the requirements of NEPA. According to FHWA noise abatement criteria, noise abatement measures must be evaluated and considered. EPG's noise specialists evaluate ADOT projects to ensure that all projects and operations comply with federal, state, and local noise abatement policies and regulations. Analysis of abatement measures includes right-of-way acquisition to provide a buffer zone, changes to horizontal and vertical alignment, insulation of some facilities if exterior noise abatement is not feasible, traffic management measures, and noise barriers. Preliminary noise barrier design includes considerations such as heights, lengths, and location. The noise abatement decision and the noise mitigation measures are incorporated into the environmental documentation.

The following flowchart demonstrates the process that is followed during noise modeling and documentation of the results:

Noise Modeling Process

Civil RightsTitle VI of the Civil Rights Act of 1964, and the Americans with Disabilities Act (ADA)

Pursuant to Title VI of the Civil Rights Act of 1964, and the Americans with Disabilities Act (ADA), ADOT does not discriminate on the basis of race, color, national origin, age, sex or disability. Persons that require a reasonable accommodation based on language or disability should contact ADOT’s Civil Rights Office at civilrightsoffice@azdot.gov. Requests should be made as early as possible to ensure the State has an opportunity to address the accommodation.

De acuerdo con el título VI de la Ley de Derechos Civiles de 1964 y la Ley de Estadounidenses con Discapacidades (ADA por sus siglas en inglés), el Departamento de Transporte de Arizona (ADOT por sus siglas en inglés) no discrimina por raza, color, nacionalidad, edad, género o discapacidad.  Personas que requieren asistencia (dentro de lo razonable) ya sea por el idioma o por discapacidad deben ponerse en contacto con la Oficina de Derechos Civiles en civilrightsoffice@azdot.gov. Las solicitudes deben hacerse lo más pronto posible para asegurar que el equipo encargado del proyecto tenga la oportunidad de hacer los arreglos necesarios.