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SR 520 – Portage Bay Bridge and Roanoke Lid Project – Noise

What to expect

Daytime work hours (as determined by the city of Seattle)

  • Weekdays: 7 a.m. – 10 p.m.
  • Weekends: 9 a.m. – 10 p.m.
  • Most construction activities will occur during the day. We will follow city of Seattle noise regulations and code, which allow daytime noise levels to average 85 dBA in most of the project area. Eighty-five dBA is roughly equivalent to a food blender, heavy traffic while you are in a car, or a noisy restaurant.

Nighttime work hours

  • Weekdays: 10 p.m. – 7 a.m.
  • Weekends: 10 p.m. – 9 a.m.
  • Activities that require temporary lane and road closures (e.g., work on the Roanoke lid or lane changeovers to the new bridge) will need to occur at night to maintain the safety of our crews and the traveling public, and to avoid causing major daytime traffic congestion.
  • Limits to the allowable level of nighttime noise will be determined through a Major Public Projects Noise Variance (MPPCNV) granted by the city of Seattle. View the MPPCNV application and submit a public comment here
Nighttime concrete pouring on the SR 520 bridge
Nighttime concrete pouring on the SR 520 bridge

Strategies and resources

Our contractor will use various strategies to reduce noise, such as installing noise-barrier fencing around parts of the construction area, prohibiting pure-tone backup alarms (the loud “beep, beep, beep” trucks often make when driving in reverse), and requiring an onsite noise inspector. We also will include financial incentives in our contract that reward the contractor for going above and beyond to reduce construction effects like noise. 

Noise monitoring

The contractor will be required to install noise meters throughout the construction area. The meters will be networked and notify us and the contractor if noise levels approach established limits.

Noise Mitigation Pilot Program

Neighbors living close to the construction area will be eligible to receive funding through the SR 520 Noise Mitigation Pilot Program. The state Legislature created this program in 2018 for the SR 520 Montlake Project. The program allows neighbors living in the immediate construction area to be reimbursed up to $3,500 for noise mitigation measures, such as noise-reducing window inserts or replacements, air conditioning to allow windows to be closed, or noise-cancelling headphones. Eligible neighbors will receive application information several months prior to construction.

Hotel vouchers

In addition to the noise mitigation program, we have developed a hotel voucher program. When nighttime work is expected to be especially noisy, such as roadway demolition, nearby neighbors will be notified in advance and offered hotel vouchers. The vouchers will include family and pet-friendly hotel options.

Noise-barrier fencing

We will require the contractor to install a noise-barrier fence around the Roanoke Lid area as an early work item to reduce noise levels caused by construction. The contractor may also place noise-barrier fences around other parts of the construction area with high levels of noise.