LAWA retained CSDA to conduct a technical feasibility and environmental review regarding the increase of the North Downwind arrival altitudes and to suggest changes to the north downwind flight path.

Aircraft arriving from the north and west during Westerly Operations follow the North Downwind Arrival Route to land at LAX. This route directs aircraft to head east parallel to the 10 freeway and make a U-turn at or pass the 110 freeway for final approach to LAX, and to create an alternative route for these arrivals. Since the Implementation of FAA’s Southern California Metroplex Project in 2017, aircraft following this route have been flying via a narrower and more concentrated flight path than before, increasing aircraft noise on the communities below.

The Communicate Roundtable proposed two options in order to provide noise relief for the communities:
A) To increase the altitudes of aircraft on the North Downwind Arrival Route and to extend the downwind leg of this route farther east to San Bernardino before aircraft can make a U-turn to head back to LAX for landing.
B) To create a new arrival procedure that directs aircraft to follow a different flight path than the North Downwind Arrival Route to join the final approach in the San Bernardino area.

CSDA performed noise modeling, emissions and fuel burn analysis as well as an evaluation of airspace conflicts. In addition, population exposure was calculated.


CSDA was retained to provide acoustical consulting services for this mixed-use project located along busy Telegraph Avenue in Oakland. The project consists of a 97-unit apartment building with Type V wood frame construction over a Type I podium. We provided an environmental noise study, along with architectural acoustics input for demising assemblies such as party walls and floor-ceiling assemblies. An analysis of HVAC and mechanical noise/vibration was also conducted.


CSDA worked with Kleinfelder and Metro as the acoustical engineer for the construction of all three phases of the Purple Line extension. CSDA is assisting with the construction noise and vibration analysis, reviewing the Contractor’s submittals and mitigation measures, conducting noise and vibration measurements, and preparing monthly noise compliance reports. Our scope includes:

• Review of contractor RFI’s and submittals with respect to construction noise and vibration
• Review of contractor’s noise and vibration monitoring plans and reports
• Preparation of monthly noise monitoring reports for submission to the City of Los Angeles and Beverly Hills monitoring conducted by Metro/TRC
• Site-specific construction noise and vibration analysis (e.g., Saban Theatre)
• Ambient noise monitoring at sensitive receivers
• Data analysis
• Design of construction mitigation measures

Continuing from the current terminus of the Metro Purple Line at Wilshire/Western, the Purple Line Extension will be completely underground and extend westward for about nine miles along Wilshire Boulevard with seven new stations. It will provide a highcapacity, high-speed, dependable alternative for those traveling to and from LA’s “second downtown,” including destinations such as Miracle Mile, Beverly Hills, Century City, and Westwood.


Phase I – As a consultant to Freytag & Associates, we performed an airplane noise assessment for the District of Columbia focused on noise impacts from changes to flight paths made out Ronald Reagan Washington National Airport (DCA). There were two major parts to the project. The first consisted of a thorough review and documentation of existing data supplemented by new investigations to document the past and current airplane noise environment over the D.C. area. Second, the team worked to develop revised air traffic procedures, acceptable to the FAA, to minimize the current noise impact over the affected areas in D.C. The overall purpose of the project was to determine what, if any, noise impacts have occurred in the District as a result of the FAA’s implementation of NextGen air traffic control procedures and routes. Finally, we identified potential flight path/route changes and other airspace modifications to reduce flyover noise in the District.

Phase II – This phase built on the previous Phase I study. Utilizing the measurement data collected in Phase I, the consultant team computed various supplemental noise metrics (Lmax, Leq, Time Above Level, etc.) to further quantify noise impacts and changes in aircraft noise due to arrivals and departures at Ronald Reagan Washington National Airport (DCA). Additional long-term field measurements were conducted and the consultant team quantified the community impacts (e.g., sleep disturbance, speech interference) according to national standards. Additionally, we identified and encouraged improvements and changes to existing noise abatement procedures and practices to reduce aircraft noise impact over the District. Specific noise mitigation recommendations were developed for presentation to airport management, the Metropolitan Washington Airport Authority (MWAA), and to the Federal Aviation Administration (FAA). The primary beneficiary of this project is the District residents, as the goal of the project is to reduce DCA aircraft noise impacts and improve residents’ quality of life through aircraft noise reduction.


CSDA was retained to provide acoustical consulting for the 1919 Market Street project in Oakland, California. We provided acoustical recommendations for the project to meet City and State code requirements. The project consists of the conversion of an existing two-story industrial building to live-work flats and town-homes as well as the new construction of a four-story residential  building. Our acoustical consulting includes schematic design review, design development review, construction document review, bidding/permit phase assistance and construction administration support, as well as preparation of a construction noise and vibration control plan.