Regional Transit Connections and Active Transportation South King County High Capacity Transit Corridor Report Alternative B2 connects to the dense bus network in West Seattle as a result of reaching the West Seattle Junction and Westwood-Highland Park urban villages. Similar to A4, it provides a connection to existing Central Link and Sounder service, but transfers at Downtown Seattle light rail stations are constrained by the required surface-to-tunnel transfer. The alternative also serves the dense pedestrian network of West Seattle Junction, scoring highly in overall active transportation system access. Travel Time and Ridership The travel time of 25 to 30 minutes between West Seattle and Downtown Seattle is the second slowest alternative due to non-exclusive at-grade operations in West Seattle. From Seattle to Burien, the 24 to 29 minute travel time is roughly equal to the light rail alternatives A3 and A5 due to the direct freeway exclusivity along SR-509. From Renton to Seattle, the travel time is between 36 and 44 minutes, longer than other alternatives but substantially better than the other BRT option, Alternative A4. Daily boardings for this alternative are between 50,000 and 66,000, of which 16,000 are from the West Seattle leg and 44,000 are along the Renton, Burien, and South Park legs. This total translates into 1,800 to 2,100 daily boardings per mile. Cost The estimated capital costs of $3.3 to $4.4 billion are lower than the other light rail alternatives but almost double the cost of Alternative A4. This is due to the extensive elevated portions of the alignment along with tunneling along SR 518 and east of I-5, in Tukwila. Construction Complexity and Maintenance Base Considerations This alternative has a moderate amount of construction complexity as a result of the elevated construction over railroads in SODO and the Duwamish Waterway. Additionally, complex tunneling and elevated sections may create challenges near SR-518 and I-5. The elevated direct access ramp in Tukwila onto I-405 could add to the complexity. However, Alternative B2 has the highest number of viable maintenance base options, with locations in SODO and Renton both as potential options. Factors to Consider for Future Planning Bus headway and fleet requirements to meet ridership demands Right-of-way needs along 35 th Avenue SW Alternative profile with semi-exclusive BRT along the Burien-Renton corridor as opposed to fully grade-separated operation 64
South King County High Capacity Transit Corridor Report Alternative B4 LRT Tunnel West Seattle Alternative B4 is an LRT alignment that travels via a mix of at-grade, elevated and tunnel profiles. It connects Downtown Seattle to West Seattle Junction, Morgan Junction, High Point, Westwood-Highland Park urban villages, White Center, South Park, Burien, SeaTac, Tukwila, and Renton. Assumptions: Downtown to W. Downtown Seattle/White Seattle to Renton Center Ridership 33 41 K 52 62 K Travel Time 11 13 min 33-41 min Capital costs only, with right-ofway* $4.2 - $5.5 B $2.5 - $3.4 B 4th Avenue Tunnel in Downtown Seattle At-grade and elevated along 6th Avenue S to S Hanford Street Elevated rail on new high bridge then through a tunnel to West Seattle Junction Surface portal near Juneau and California intersection Elevated via California Avenue SW and via 35th Avenue SW to White Center A second LRT line would connect from Downtown Seattle via Georgetown elevated/atgrade to South Park and Burien via SR-509 from Seattle Elevated/at-grade to SeaTac, Tukwila and Renton via SR-518, Strander Boulevard and Grady Way with S 2nd/3rd Street couplet in Renton. At-grade on Logan Ave N. 10 minute headways Profile Total 85 to 103 K Non-exclusive At-grade 0% Semi-exclusive At-grade 22% Exclusive Elevated 62% Exclusive Tunnel 16% $6.8 - $9.0 B *Draft costs (2014$) shown are conceptual level estimates only and are used for purposes of comparison 65 28.6 miles
South King County High Capacity Transit Corridor Report Summary of Findings (B4) 78% exclusive and 22% semi-exclusive running way Higher potential for noise and visual effects Serves South Park and the West Seattle Junction and Westwood-Highland Park urban villages, but not the Delridge corridor High potential for right-of-way effects Higher ridership potential Highest cost and engineering complexity Reliability Alternative B4 provides 78% exclusive and 22% semi-exclusive running way throughout the corridor via a mix of elevated and at-grade profiles. It has the lowest level of congestion-related travel time delays as a result of the substantial portion that is elevated. Environment and Community The alternative has higher noise and visual effects as a result of the elevated segments. Additionally, there are moderate affects to on-street parking expected due to structure required for the elevated alignment along California Avenue SW and 35 th Avenue SW in West Seattle. Transportation System Effects Depending on the final elevated design, there may be effects to the Spokane Street Viaduct and the SR- 99 interchange. Potential effects to shipping operations near Harbor Island or possible effects to the existing West Seattle Bridge depend on the crossing alignment. There are potential effects to shipping patterns through the Duwamish Waterway near the 1st Avenue crossing. Although the alignment runs along SR-509, operations along this corridor are not expected to be substantially affected. The Burien Transit Center may require a major modification or relocation depending on the light rail alignment. Additionally, the Tukwila International Boulevard Station may require some modifications in order to provide a seamless connection between the current elevated station and a proposed underground station. A tie-in to the Renton Transit Center is expected to require modifications. Alternative B4 is expected to have a moderate effect on existing transportation operations, particularly in Renton along Rainier Avenue S due to high levels of congestion in that area and an at-grade LRT profile. New Right-of-way While Alternative B4 operates along a similar alignment as Alternative B2, right-of-way effects differ for the portion within West Seattle. A substantial number of acquisitions are likely along California Avenue SW and at each of the intersections where the elevated alignment turns. Some acquisitions are required in Burien south of the transit center and in Renton near the transit center. Minimal acquisitions are required along SR-518 or in Tukwila. Economic Development Like Alternative B2, B4 also connects all three station areas that are highly rated for transit-oriented development potential, including Southcenter, West Seattle Junction, and South Park. Alternative B4 also has the highest concentration of jobs and access to community facilities due to the spatial coverage of key opportunity areas. 66
Regional Transit Connections and Active Transportation South King County High Capacity Transit Corridor Report The West Seattle connections to the bus network provide similar benefits as in Alternative B2. While the rail-to-rail connection at Tukwila International Boulevard Station and at the Tukwila Sounder station supports transfer opportunities, the connections involve grade differences and would not be immediately adjacent to one another. The alternative serves the dense pedestrian network of West Seattle and Morgan Junctions, scoring highly in overall active transportation system access. Travel Time and Ridership Travel time between Downtown Seattle and West Seattle is expected to be between 11 and 13 minutes, similar to Alternative A5 due to the direct elevated connection. The alternative is expected to provide travel times from Downtown Seattle to Burien that are better than other alternatives, with average travel time estimated at 20 to 25 minutes. From Seattle to Renton, the travel time will be between 33 and 41 minutes as a result of the more direct SR-509 connection. Daily boardings for this alternative are between 85,000 and 103,000, of which 37,000 are from the West Seattle leg and 57,000 are along the Renton, Burien, and South Park leg. This total translates into 3,000 to 3,600 daily boardings per mile, the highest of all alternatives. Cost With estimated capital costs of $6.8 to $9.0 billion, this alternative is one of the most expensive options as a result of the tunneling portions and substantial amount of elevated profile. Construction Complexity and Maintenance Base Considerations Similar to Alternative B2, challenges exist where the alignment must cross railroads rights of way in SODO and the Duwamish Waterway. Additionally, the tunnel portion in West Seattle will add to the construction complexity while the topography of West Seattle will create construction challenges for the elevated portion. Construction of new elevated rail over the UP and BNSF crossings in SODO and in Tukwila involve complex construction procedures. Alternative B4 has viable maintenance base locations both in SODO and in Renton due to geographic reach into the two areas. Factors to Consider for Future Planning Alternative profile in West Seattle that extends the tunnel portion along California Avenue SW or an alternative profile that transfers to at-grade along 35 th Avenue SW Right-of-way needs along California Avenue SW 67
South King County High Capacity Transit Corridor Report Alternative C5 LRT to White Center; Burien/Renton BRT Alternative C5 includes an LRT alignment with connections between Downtown Seattle, West Seattle Junction, Morgan Junction, High Point, Westwood-Highland Park urban village, and White Center. Alternative C5 also includes an east-west BRT route connecting Burien, SeaTac, Tukwila, and Renton.. Connections between these centers and Downtown Seattle, Sea-Tac Airport, Angle Lake Station, via LRT can be made at Tukwila International Boulevard Station. Assumptions: 4th Avenue Tunnel in Downtown Seattle with elevated rail on high bridge to West Seattle and White Center Mixed traffic BRT between Burien and Renton Connections to Central Link at Tukwila International Boulevard Station for trips to/from Downtown Seattle and points south. 10 minute headways Profile Downtown to Downtown Downtown West Seattle to Burien to Renton Ridership 32 39 K Travel Time 11-13 min Capital costs only, $3.4 $4.5 B with right-ofway* Total 39 to 48 K 40-49 min 48-58 min Non-exclusive At-grade 32% Semi-exclusive At-grade 13% Exclusive Elevated 46% Exclusive Tunnel $4.2 - $5.5 B *Draft costs (2014$) shown are conceptual level estimates only and are used for purposes of comparison 68 21.2 miles 9%
South King County High Capacity Transit Corridor Report Summary of Findings (C5) 55% exclusive and 13% semi-exclusive running way Higher potential for noise and visual effects Serves the West Seattle Junction and Westwood-Highland Park urban villages but not the Delridge Corridor High potential for right-of-way effects in West Seattle Lowest effect on traffic operations Medium ridership potential Higher cost and engineering complexity Reliability Alternative C5 provides 55% exclusive and 13% semi-exclusive running way throughout the corridor via a mix of elevated and at-grade LRT profiles with BRT at-grade between Burien and Renton. Environment and Community The alternative has potentially higher noise and visual effects because of the elevated segments. Additionally, there are moderate affects to parking expected due to the alignment along California Avenue SW and 35 th Avenue SW in West Seattle. Transportation System Effects Depending on the elevated design, there may be effects to the Spokane Street Viaduct and the SR-99 interchange. Potential effects to shipping operations near Harbor Island or to the existing West Seattle Bridge depend on the crossing alignment. Overall effects to transportation operations are expected to be moderate, with the highest effects along Rainier Avenue S in Renton. New Right-of-way Although the number of full acquisitions is lower than other alternatives, the total right-of-way cost is high due to the elevated portion in West Seattle. Full acquisitions are required at Alaska Junction and along California Avenue SW due to the elevated alignment curvature requirements. The effects in Renton are substantially less than those for other alternatives because of existing roadway width and Business Access and Transit (BAT) lanes. Economic Development Alternative C5 connects to many of the major residential and employment centers, with high potential for transit-oriented development, that Alternatives A3 and A4 miss, including the West Seattle Junction and Westwood-Highland Park urban villages. However, Alternative C5 does not connect to as many community facilities as compared to other alternatives. 69
Regional Transit Connections and Active Transportation South King County High Capacity Transit Corridor Report The alternative provides good bus connections within West Seattle. It also provides connections to existing Light Rail and Sounder service in Downtown Seattle and in Tukwila. This alternative serves the dense pedestrian network of West Seattle and Morgan Junctions, scoring highly in overall active transportation system access. Travel Time and Ridership The elevated connection between West Seattle and Downtown Seattle is expected to take between 11 and 13 minutes. The travel times between Seattle and Burien will be longer than other alternatives at 40 to 49 minutes due to the transfer required from BRT to Central Link at Tukwila International Boulevard Station. The travel time between Renton and Downtown Seattle is expected to be 48 to 58 minutes due to the required transfer. Daily boardings for this alternative are predicted to be between 39,000 and 48,000, of which 8,000 to 10,000 are forecast along the BRT segment and 32,000 to 39,000 are LRT boardings. This translates into roughly 1,900 to 2,300 new daily boardings-per-mile. Cost Alternative C5 is estimated to cost between $4.2 and $5.5 billion. A large portion of the cost is due to the substantial elevated segments in West Seattle. Construction Complexity and Maintenance Base Considerations Similar to Alternative B4, challenges exist with the crossing of the railroads in SODO and the Duwamish Waterway. Additionally, the tunnel portion in West Seattle will add to the construction complexity while the terrain of West Seattle will create construction challenges for the elevated portion. Compounding this is the disadvantage this alternative has with regards to maintenance base locations. Since this alternative has a fleet of BRT and LRT vehicles, two maintenance facilities locations are required. Only one maintenance facility site in southern SODO could serve for the LRT vehicles while two location options in Renton could function for BRT vehicles. Factors to Consider for Future Planning Alternative profile through West Seattle reflects the alignment of Alternatives A5 or B4 70
South King County High Capacity Transit Corridor Report 8.4 Downtown Seattle Options The Downtown Seattle design options were primarily differentiated by cost. The tunnel options are more costly on the order of $1 billion. Ridership is generally similar with a decrease in daily boardings associated with option D1 due to distance from the downtown business core. Elevated options D1 and D2 have somewhat faster travel times. Findings are summarized in Table 8-2. Tunnel options via 2 nd or 3 rd Avenue could also be considered. It should be noted that the DSTT travels under 3 rd Avenue, and the Elliott Bay Interceptor (sewer main) is located under 2 nd Avenue, in addition, BNSF s Great Northern Tunnel and the future SR-99 tunnel all present constraints. Table 8-2. Findings - Downtown Seattle Options D1 D2 D3 / D4 D5 Downtown Option Elevated LRT along Alaskan Way in Downtown Seattle and via 1st Avenue S through SODO Elevated LRT along 2nd Avenue Tunnel via 5th or 6th Avenue in Downtown Seattle. BRT at-grade one-way couplet on 2nd / 4th Avenues Findings Costs are approximately $900 million less than 4th Avenue tunnel option Roughly 5,000 fewer daily boardings Difficult terrain and distance for connections to Central Link and downtown bus service Faster travel time by 3 to 4 minutes Higher Right-of-Way cost due to elevated profile, but requires few parcel acquisitions due to WSDOT Right-of-Way width Higher visual effects to business and potential effects to park areas Capital costs are approximately $800 million less than 4th Avenue tunnel option Approximately 1,000 more daily boardings Connections to Central Link are more difficult from elevated to tunnel stations Less than a minute savings in travel time Higher right-of-way cost due to elevated profile, but requires fewer parcel acquisitions Higher visual and noise effects Minimal change in daily boardings Travel times are slightly longer on 6th Avenue $150 to $200 million higher capital cost, due to added tunnel length Slightly higher right-of-way costs expected due to narrow width of 5th and 6th Avenues Similar results to main alternative Both this and the main alternative would be in atgrade mixed traffic 71
South King County High Capacity Transit Corridor Report 8.5 Risk Assessment Summary The risk assessment analysis established confidence intervals for the South King County HCT Corridor Level 2 alternatives related to cost, schedule, technical, environmental, political, and other unknowns. Risk analysis is the systematic evaluation of uncertainty about the scope, cost, and duration of a project. This uncertainty is in the form of risks that a project could encounter during the course of its development, from planning through construction. More detailed explanation of this process and the evaluation results can be found in the Risk Assessment Memorandum. A Risk Assessment Workshop took place with Sound Transit staff and the project team, and the group reviewed the risk register and evaluated potential level of risk in a set of risk categories. Each of the final six alternatives was evaluated along with the corridor study area as a whole. The categories included the following: Technical: Utility conflicts, engineering complexity Legal/Process: Local agency permitting, environmental clearance, and legal challenges. Environmental: Wetlands, cultural and historic resources, shoreline, Army Corps of Engineers permits, conflicts with other plans, and endangered or threatened plants and animals. Visual & noise were also included. Political/ Stakeholder: Political, legislative, agency, voter, and agency support. Communications: Complexity and/or controversy that will require early and intensive communication with stakeholders, riders, public, other consumers as legitimate partners. Financial: ROW, high cost elements. Based on the workshop analysis, the following corridor elements were assigned the highest risks: The risk of creating an elevated line or tunneling was identified as a risk for all corridor alternatives that contained these features. The risk of tunneling in Downtown Seattle was identified as a higher risk than tunneling elsewhere. There are taller buildings with deeper foundations, higher valued right-of-way, and other civil infrastructures present that could increase budget and extend the schedule. For this reason, tunneling in Downtown Seattle received a high risk for both schedule and budget, and the largest overall risk scoring. Complex tunneling engineering issues are also present in West Seattle and Tukwila due to topography and other transportation infrastructure. Both areas received a medium risk score. Tunnel Station construction in Downtown Seattle resulted in a medium risk score for both schedule and risk. This includes the risks associated with tying in existing tunnel stations with new stations. 72
8.6 Intelligent Transportation Systems Summary South King County High Capacity Transit Corridor Report As part of the Level 2 evaluation, the alternatives were analyzed to identify any Intelligent Transportation Systems (ITS) solutions that may be needed in the corridor. The ITS elements that were evaluated include fiber optic communication interconnect and transit signal priority (TSP). TSP alters the normal operations of a traffic signal to give priority to an on-coming bus or train, thus improving its efficiency. TSP works best with a fiber optic interconnect communications link to the overall signal system and remote operations centers (i.e. Seattle DOT, Sound Transit). Many of the alternatives would leverage existing TSP and fiber infrastructure installed throughout the corridor. Table 8-3 summarizes the ITS needs by area, and Table 8-4 summarizes the needs by alternative. More detailed analysis can be found in the ITS Analysis Memorandum. 73
South King County High Capacity Transit Corridor Report Table 8-3. Intelligent Transportation Systems Needs by Area Corridor or Area Jurisdiction New TSP Intersections Opportunities Delridge Way SW Seattle 4-8 Some intersections will require new fiber interconnect 35 th Avenue SW Seattle 10 No new fiber interconnect required 1 st Avenue and 4 th Avenue Burien and King County 8 11 Will require new fiber interconnect in this corridor Southcenter Area Tukwila 1 2 No new fiber interconnect required Rainier Avenue N and S 2 nd Street Renton 0 3 No new fiber interconnect required Table 8-4. Intelligent Transportation Systems Needs by Level 2 Alternatives Alternative Mode TSP Locations A3 LRT 14 intersections in the corridor should be equipped with TSP where fiber interconnect exists in Seattle, Burien and Renton New fiber interconnect would be needed to provide TSP at 11 intersections along 4 th Avenue S and 1 st Avenue S in Burien and in Seattle along portions of Delridge Way A4 BRT 9 intersections in Seattle, Burien and Tukwila should be equipped with TSP where fiber interconnect exists in Seattle, Burien and Renton New fiber interconnect would be needed to provide TSP at 6 intersections along 4 th Avenue S and 1 st Avenue S A5 LRT 10 intersections in the corridor should be equipped with TSP where fiber interconnect exists in Seattle, Burien and Renton New fiber interconnect would be needed to provide TSP at 7 intersections along 4 th Avenue S and 1 st Avenue S in Burien B2 BRT 11 intersections in the corridor should be equipped with TSP where fiber interconnect exists in Seattle, Burien and Renton B4 LRT 8 intersections in the corridor should be equipped with TSP where fiber interconnect exists in Seattle, Burien and Renton New fiber interconnect would be needed to provide TSP at 3 intersections along 1 st Avenue S in Burien C5 LRT/BRT 7 intersections in the corridor should be equipped with TSP where fiber interconnect exists in Seattle, Burien and Renton 74
South King County High Capacity Transit Corridor Report 9 REFERENCES 9.1 South King County HCT Corridor Study Fehr & Peers and Sound Transit. 2013. Baseline Corridor Report. South King County High Capacity Transit Corridor Study. October. Fehr & Peers and Sound Transit. 2013. Initial Options Screening Results Report. South King County High Capacity Transit Corridor Study. December Fehr & Peers and Sound Transit. 2014. Level 1 Evaluation Memorandum. South King County High Capacity Transit Corridor Study. June. Fehr & Peers and Sound Transit. 2014. Level 2 Evaluation Memorandum. South King County High Capacity Transit Corridor Study. June. Fehr & Peers and Sound Transit. 2014. Conceptual Design Files. June. Fehr & Peers and Sound Transit. 2014. Conceptual Cost Estimates. June. Fehr & Peers and Sound Transit. 2014. Risk Assessment Memorandum. South King County High Capacity Transit Corridor Study. March. Fehr & Peers and Sound Transit. 2014. System Integration, Operations, and Maintenance Memorandum. South King County High Capacity Transit Corridor Study. June. Fehr & Peers and Transpo Group. 2014. ITS Analysis Memorandum. South King County High Capacity Transit Corridor Study. June. Fehr & Peers and Sound Transit. 2014. Station Area Assessments. South King County High Capacity Transit Corridor Study. August. 9.2 Other Related Documents Sound Transit (formerly Regional Transit Authority). 1996. Sound Move The Ten-Year Regional Transit System Plan. Central Puget Sound Regional Transit Authority, Seattle, Washington. May. Sound Transit. 2005. Regional Transit Long-Range Plan. Central Puget Sound Regional Transit Authority, Seattle, Washington. July 7. Sound Transit. 2008. Sound Transit 2: A Mass Transit Guide The Regional Transit System Plan for Central Puget Sound. Central Puget Sound Regional Transit Authority, Seattle, Washington. July. Sound Transit. 2013. Ridership Forecasting Model. Central Puget Sound Regional Transit Authority, Seattle, Washington. July 12. Puget Sound Regional Council (PSRC). 2009. VISION 2040: The Growth Management, Environmental, Economic, and Transportation Strategy for the Central Puget Sound Region. Adopted April 2998. Amended May 2009. Available at http://psrc.org/ projects/vision/index.htm. Seattle, Washington. December. 75