Planning commission approves six-home subdivision at 640 Lake Haven Drive despite noise concerns

The Sunnyvale Planning Commission on Jan. 13 approved a special development permit and vesting tentative map to allow construction of six two‑story single‑family homes and one common lot at 640 Lake Haven Drive.

Planner Mary Jaiprakash told the commission the one‑acre site, zoned R0 with a planned development combining district, proposes six ownership homes and is exempt from CEQA as urban infill development. The project seeks five deviations (reduced lot area and width and three setback variances) and triggers commission review because the floor‑area ratio exceeds 45 percent.

The commission’s discussion centered on two technical concerns: exterior noise levels from adjacent Highway 101 and air quality exposure. Commissioner Pine said she read the general plan’s noise table as showing a 60‑decibel “normally acceptable” level for detached single‑family homes and asked why staff used 65 decibels for comparison. Planner Mary Jaiprakash said the project’s location next to a major transportation corridor and the project’s townhouse‑like layout led staff to use 65 dB as the comparison standard, and cited General Plan noise footnotes that allow discretion when a detailed site‑specific noise study and mitigation are provided.

The project team submitted an acoustical study showing interior noise mitigation measures and exterior mitigation options; the study found some units could meet stricter limits but others could not reach lower exterior targets even with extensive (and cost‑prohibitive) measures such as very tall sound walls. Applicant architect Ted Triplett said the team had evaluated many mitigation measures and would ensure interior noise abatement and tenant information are provided in owner manuals.

On air quality, Jaiprakash said the project’s air study and a health‑risk analysis showed exposures below Bay Area Air Quality Management District screening levels; staff recommended MERV‑13 filters and at least one air exchange per hour as conditions of approval. Commissioners pressed whether those measures would be maintained after sale; staff said the project’s conditions of approval and the CC&Rs would document recommended ongoing measures.

The proposal also exceeds parking requirements on site (staff said the project provides four unassigned common spaces in addition to required on‑lot parking). Staff said the five requested deviations are marginal and primarily internal to the new private street, not visible from the public right of way, and therefore reasonable.

Vice Chair Davis moved to approve the special development permit and vesting tentative map with modified findings acknowledging the applicable exterior noise standard is 60 dB while finding the project may be consistent with General Plan Safety and Noise policies (including SN‑8.9) given the site‑specific noise study and incorporated mitigation; the chair seconded. The motion passed 6–0 with Commissioner Shukla absent.

The commission’s action is subject to a 15‑day appeal period ending Jan. 28, after which the approvals will proceed to permit and building‑plan review.