Chapter 12 - Noise

• Noise Control Act of 1972
• National Environmental Policy Act (NEPA)
• Title 23 Code of Federal Regulations (CFR) Part 772 (23 CFR 772)

For a federal or Federal-aid project, the noise technical report and the noise section of the environmental document must reflect the following basic analytical steps for all alternatives:

• Is the project a Type I project?
• If the project is a Type I project, would the project result in a traffic noise impact?
• If the project would result in a traffic noise impact, noise abatement must be considered.
• Is the noise abatement that is considered reasonable and feasible?

If traffic noise impacts are predicted, noise abatement measures must be considered and evaluated. Preliminary noise abatement design includes considerations such as barrier heights, lengths, and location (see TeNS Section 5 for additional details). Noise abatement is only considered where frequent human use occurs and a lowered noise level would be of benefit.

Noise abatement will be included as part of the project only if constructing the abatement is reasonable and feasible. Feasibility is an engineering consideration and includes factors such as access requirements for driveways, topography, presence of underground and above ground utilities, and safety. Noise abatement must be predicted to reduce noise by at least 5 dB at an impacted receptor to be considered feasible from an acoustical perspective.

The overall reasonableness of noise abatement is determined by the following three factors:

• the noise reduction design goal (7 dB for at least one or more receptors),
• the cost of noise abatement, and
• the viewpoints of benefited receptors (including property owners and residents of the benefited receptors).

Noise Analysis Under the California Environmental Quality Act (CEQA)

Noise analysis for projects under CEQA centers on whether the project or the proposed noise abatement would result in significant adverse environmental effects. Whether an increase in future noise level would result in a significant effect for purposes of CEQA is determined by comparing the existing noise level (or baseline environmental setting) to the predicted noise level with project. The CEQA noise analysis is completely independent of the 23 CFR 772 noise analysis, which is centered on noise abatement criteria. Under CEQA, the assessment entails looking at the setting of the noise impact and then how large or perceptible any noise increase would be in the given area. Key considerations include: the uniqueness of the setting, the sensitive nature of the noise receptors, the magnitude of the noise increase, the number of residences affected, and the absolute noise level. The significance of noise impacts under CEQA is determined by the Project Development Team (PDT) and is based on the considerations above. For additional information, see Section 7 of the Noise Protocol.

There is no "resource" agency for highway traffic noise. It is the responsibility of the Department (under NEPA Assignment) through the approval of environmental documents to ensure compliance with the provisions of 23 CFR 772. For "state-only" projects, the Department is responsible for the environmental document. For further guidance, see SER Volume 1, Chapter 38, "NEPA Assignment."

Property within the state's right-of-way is not subject to local government ordinances. However, all possible effort should be made to comply with the local ordinances.

Links to counties, cities, and local noise ordinances may be found on the following websites:

• California Local Codes and Charters
• California State Government Contacts
• California State Association of Counties

The results of a detailed traffic noise analysis are documented in the Noise Study Report (NSR). Section 3 of the Noise Protocol and Section 6 of the Technical Noise Supplement to the Traffic Noise Analysis Protocol (TeNS) describe in detail the process of developing the NSR. The Noise Abatement Decision Report (NADR) is a report that documents the abatement considerations. Both the Noise Study Report and the Noise Abatement Decision Report must be summarized in the draft environmental document.

Any lead acoustical analyst or staff member responsible for the assessment of traffic noise impacts, traffic noise abatement, or review and approval of final noise reports shall at a minimum have a BS or BA degree in a related field and 5 years of demonstrated experience.

In lieu of 5 years of experience, equivalent qualifications as determined by the Caltrans Division of Environmental Analysis or successful completion of all of the following will be allowed:

• INCE Fundamentals examination;
• Traffic Noise Fundamentals and Traffic Noise Modeling with TNM training offered by Bill Bowlby and Associates, Inc.; and
• NHI Web-Based Training for Highway Noise Courses 142086 thru 142094.

Section 6 of the TeNS describes the proper format of the NSR. A good NSR contains all the necessary information for the reviewer to understand the report with minimum need for further clarification and consultations. A good noise study report contains:

• Detailed discussion of: land uses, existing and future noise levels, proposed abatement, and the reasonable and feasibility analysis
• Visual aids: Vicinity maps, project area maps, layouts that clearly indicate the location of affected receptors relative to the project, proposed location of barriers, topographic information, etc.
• Technical Information: date, time, location, and duration of noise measurements; instrumentation used; inclusion in the appendices of any references mentioned in the report; modeling input and output files; and projected traffic volume data
• Evaluation of construction noise impacts

The draft NSR must be reviewed, at a minimum, by the District noise specialist (for consultant-prepared documents) and the District Environmental Planner/Generalist responsible for the environmental document. The NSR is approved by the noise specialist’s supervisor (District Branch Chief). For further guidance, see SER Volume 1, Chapter 38, "NEPA Assignment."

Local Assistance Projects - Noise Study Reports prepared in support of local agency Federal-aid transportation projects "off" the SHS have the same review and approval requirements but are processed through the District Local Assistance Engineer (DLAE). The report shall be reviewed by the District noise specialist and the District Local Assistance Environmental Planner/Generalist, and approved by the District noise specialist's supervisor (District Branch Chief).

The NSR is reviewed to ensure that:

• it complies with the requirements of all applicable federal laws, regulations, policy and guidance
• the report format and content are consistent with the SER, and
• the report summary and conclusions are consistent with the information included in the environmental document

Following the Department's internal review of the NSR, the study may be finalized. For further guidance, see "SER Volume 1, Chapter 38, NEPA Assignment."

This information should be documented in the Environmental Impact Report (EIR) prepared for the Regional Transportation Plan (RTP) and serve as a building block in subsequent decision making.

An RTP requires the preparation of a CEQA environmental document, normally a program or master EIR. Caltrans encourages the Metropolitan Planning Organizations/ Regional Transportation Planning Agencies (MPO/RTPA) to include the following information, as appropriate, in the environmental document for the plan:

• Project conceptual design (highway on new alignment; substantially change vertical or horizontal alignment of existing highway; or increase number of through lanes; realignment, etc).
• Land uses (with reference to Noise Abatement Criteria categories).
• Locations of potentially sensitive receptors within subarea or corridor under study (such as hospitals, schools, churches, libraries, auditoriums, public meeting rooms, motels, hotels, residences, recreational facilities and lands on which serenity and quiet are of extraordinary importance and which serve an important public need).
• Existence of local noise ordinances covering the corridor or subarea.