and accurate reflection of all the waterway needs, they wanted to ensure significant collaboration from a broad range of waterway users. As the data analysis began, concurrent with outreach efforts, District 11 realized it wanted more granularity on public concerns regarding certain areas where conflicting waterways uses were likely. Specifically, the District sought public input regarding the two California Wind Energy areas, the Navy’s Pacific Missile Range, and the approaches to San Francisco Bay. It released a Notice of Inquiry in the Federal Register with an additional 28 questions regard- ing those areas to expand the Coast Guard’s dialog with the maritime community. 7 All comments received for both notices were considered in the drafted PARS rec- ommendations and adjudicated as part of the study. Data Analysis The data analysis was an enormous task conducted by the Coast Guard Navigation Center (NAVCEN) and District 11. NAVCEN’s vessel traffic analysis was based on Automatic Identification Systems (AIS) transponder data for 10 port entrances along the West Coast. The District completed a similar analysis for offshore vessel traffic which included data for both Districts 11 and 13. The offshore analysis considered a number of data points including, but not limited to: • vessels (calendar years 2017–2021) • vessel density (calendar years 2017–2021) • type of vessel • seasonal routing changes • industry agreements • recommended routes • changes in traffic patterns since 2012 • marine sanctuaries • whale location data • environmental data • fishing industry data • marine incidents • casualties The years 2012, 2015, and 2017 through 2021 were selected to determine both the average vessel activity over the last five years as well as long-term traffic pattern trends over the last decade. This was done to showcase changes given various AIS carriage requirements and environmental regulation shifts. The data was used to create track-lines, which resulted in hundreds of thou- sands of individual transits from baseline to outside the exclusive economic zone. This data could then be broken down into components for individual study, like those noted above, or further processed for many other statisti- cal analyses. Using geographic information system software, the District 11 Waterways staff overlaid the vessel traffic data with other significant ocean uses and obstructions that included: • Bureau of Ocean Energy Management wind energy areas • National Oceanic and Atmospheric Administration (NOAA) national marine sanctuaries • marine life statistics • NOAA fishing vessel data • space industry marine activities • military practice ranges The resulting maps offered details for a compre- hensive understanding of vessel traffic patterns and projected conflicts with existing and emerging uses of Pacific Coast waters. These statistical analyses were criti- cal to developing marine spatial planning with the least disruptive solution that met all avoidance needs. The 90 Percent Solution Fits 100 Percent In many projects, 90 percent would not necessarily be a respectable metric to measure success. For the PAC- PARS project, where wide-ranging needs and concerns of waterway uses and stakeholders were considered, the team aimed to accommodate all reasonable waterways uses to the extent practical while providing for safety of navigation along the Pacific Coast. Finding this solution inevitably resulted in some sharing and concessions, but Districts 11 and 13 found ways to ensure each conflicting space usage worked to protect the safe navigation of ves- sels without encroaching on other uses. Conclusion The waterways are national priorities due to their energy resources, sacred sites, critical supply chain role, particu- larly pertaining to food security, importance to national defense, and opportunity for exploration and adventure. The ultimate goal of the PARS process was to maintain those priorities while allowing emergent technologies to flourish and to provide an unobstructed space for vessels’ safe navigation. Balancing overlapping water- ways’ uses is critical to the strategic needs of the United States and its citizens. As the uses for the sea continue to change, those strategic needs will as well. About the author: LCDR Sara Conrad has served in the U.S. Coast Guard for 14 years, serving in many capacities, most recently as the Pacific Area project manager for the PAC-PARS. She has received three Coast Guard Com- mendation Medals, two Achievement Medals, and three Meritorious Unit Commendations. Endnotes: 1. Terry Mort, The Hemingway Patrols: Ernest Hemingway and His Hunt for U-Boats, Scribner, 2010, p. 15. 2. Terry Mort, The Hemingway Patrols: Ernest Hemingway and His Hunt for U-Boats, Scribner, 2010, p. 61. 3. Ports and Waterways Safety Act (PWSA)(P.L. 95-474, 33 U.S.C. 1223(c)) 4. 87 FR 52587 5. Regulations.gov; USCG-2021-0345 6. 86 FR 40791 7. 87 FR 10757 Summer 2023 Proceedings 87