Brief Description: Addressing noise abatement in transportation projects.

Sponsors: Representatives Jarrett, Clibborn, Eddy, Springer, Hunter, Santos and Kenney.

Hearing Date: 2/26/07

Staff: Kathryn Leathers (786-7114).

Background:

During the development and planning phases of most transportation projects, the Washington State Department of Transportation (WSDOT) typically conducts a community-impact assessment to evaluate the effects of a transportation project on a community and its quality of life. This assessment addresses a range of potential environmental and community impacts, including noise impacts, and is a process by which public input and involvement is sought and considered as the project is developed and project costs are determined.

Assessment of Noise Impacts
Federal law requires that, for certain types of federally-funded transportation projects, states establish and follow an evaluation process that determines: whether the project has an impact on noise levels; and, if there is an impact, whether mitigation of that impact is both reasonable and feasible. If a state follows the federal process, it meets the federal standard.

The federally-funded transportation projects for which a state must establish such an evaluation process are referred to as Type I transportation projects. Type I transportation projects are those that: (a) involve construction of a new highway; (b) involve a significant movement of the road (significantly changing the horizontal or vertical alignment); or (c) add lanes to existing roads.
This evaluation process is not required under federal law for Type II projects. Type II projects are retrofit projects.

Washington has a policy in place that follows the federal process. Under current policy, WSDOT evaluates placing abatement for traffic noise from highways for Type I and some Type II transportation projects. For Type II projects, WSDOT maintains a prioritized retrofit list in order to provide noise abatement to these projects as funding allows. One criteria for being added to the Type II priority list is that qualifying neighborhoods must have been constructed prior to May 16, 1976.

For Type I projects, the federal government has identified a noise level (or noise threshold) that is deemed to cause an impact on a community. Noise levels are established in terms of A-weighted decibels (dBA), units for measuring sound on a statistically weighted scale that most closely represents the range of human hearing. The average human ear picks up changes in noise at around 3 dBA of change.

The federally-established decibel noise impact level is typically used by states to make the initial determination of whether the project has a noise impact requiring further assessment for mitigation purposes. If the threshold decibel level is met, the next step is to determine whether mitigation of that impact is feasible and reasonable.

The feasibility determination involves an assessment of engineering constraints and whether, even if engineering is possible, the barrier will actually reduce noise levels. If mitigation is deemed feasible, the next step is to determine whether mitigation is also reasonable. The reasonableness determination is a mitigation cost assessment.

Mitigation typically involves building a noise barrier to reduce noise impacts. The average cost of noise walls (typically the least expensive noise mitigation alternative) is approximately $53 per square foot. Construction of a 14-foot high wall costs about $3.9 million per mile. Barriers built in urban areas tend to be more expensive due to the cost of moving existing structures such as retaining walls, water pipes, and electric utilities.

Summary of Bill:

Existing noise abatement assessment and mitigation policies, performed by WSDOT as such policies relate to federal noise abatement requirements for certain types of roadway projects, are substantially codified. The noise abatement assessment and mitigation policies are also extended to include a broader class of road projects than under current practice.

The WSDOT is required to identify a community's preferred mitigation alternative and construct that preferred alternative if the WSDOT determines that it is both feasible and reasonable.

Existing noise abatement assessment and mitigation policies are modified to require that more stringent standards are applied.

Appropriation: None.

Fiscal Note: Requested.

Effective Date: The bill takes effect 90 days after adjournment of session in which bill is passed.