9.18.045B Development restrictions.
A. New residential structures shall not be approved for construction if the exterior Ldn anywhere along the proposed building lines of the structure exceeds 65 dBA unless sound attenuation measures are incorporated into the site design and/or the design and construction plans of the structure which are intended to reduce the maximum interior Ldn as follows:
1. Forty dBA or lower for sleeping areas; and
2. Forty-five dBA or lower for nonsleeping areas.
B. Play area equipment shall not be installed as part of an exterior public or private community recreation area if the exterior Leq (daytime) at the play area site exceeds 55 dBA unless sound attenuation measures including, but not limited to, berms, barriers and/or buildings are incorporated into the site design which are intended to reduce the maximum exterior Leq (daytime) to 55 dBA or lower.
C. Arterial improvement requirements in Class A EDNAs are as follows:
1. In Class A EDNAs, arterial improvement projects not including the addition of walkways, bicycle lanes and minor widening must include a noise analysis of the affected environment by a qualified noise consultant if:
a. The existing exterior noise level exceeds 67 dBA peak hour Leq; or
b. The projected exterior noise level as a result of the project is estimated to increase beyond 67 dBA peak hour Leq; or
c. The exterior noise level is expected to increase by five dBA more as a result of the project.
2. The point of exterior noise level measurement for purposes of this subsection will be five feet above existing grade anywhere along a parallel line 60 feet on either side of the arterial centerline.
3. Noise mitigation measures, intended to reduce exterior noise levels to 60 dBA Ldn or lower, will be approved by the director of design and development if the cost of noise mitigation is included in the CIP budget, or by the city council if additional funds for noise mitigation are required, in consideration of the following factors:
a. Whether reasonable noise mitigation measures are available which will reduce exterior noise levels by three dBA or more; and
b. Whether the financial impacts of noise mitigation measures are not disproportionate to the overall cost of the arterial improvement project; and
c. Whether benefited property owners contribute to the cost of mitigation; provided, that this factor only applies if existing exterior noise levels exceed 67 dBA peak hour Leq; and
d. Whether the benefited community is supportive of noise mitigation measures. (Ord. 5719 § 11, 2007.)