HIGH-CAPACITY TRANSIT CORRIDOR STUDY South King County Corridor South King County High-Capacity Transit Corridor Study Corridor Report August 2014
South King County High Capacity Transit Corridor Report TABLE OF CONTENTS EXECUTIVE SUMMARY... S-1 1- INTRODUCTION... 1 1.1 Project Background... 1 1.2 Goals, Objectives, and the Need for HCT... 4 1.3 Problem Statement Summary... 5 2- PREVIOUS STUDIES AND FINDINGS... 6 2.1 Plans, Policies, and Legislation... 6 2.2 Previous Studies... 8 3- CORRIDOR CHARACTERISTICS... 10 3.1 Overview... 10 3.2 Land Use / Demographics... 12 3.3 Travel and Transit Markets... 18 3.4 Transportation and Utilities... 22 3.5 Natural Environment... 29 4- PROJECT GOALS AND OBJECTIVES... 31 5- EVALUATION CRITERIA AND METHODOLOGIES... 32 5.1 Screening Process... 32 6- INITIAL SCREENING... 33 7- LEVEL 1 ALTERNATIVES AND EVALUATION... 33 7.1 Level 1 Alternatives... 33 7.2 Level 1 Criteria... 40 7.3 Level 1 Evaluation Summary... 41 8- LEVEL 2 ALTERNATIVES AND EVALUATION... 46 8.1 Level 2 Alternatives... 46 8.2 Level 2 Evaluation Criteria... 46 8.3 Level 2 Evaluation Results... 50 8.4 Downtown Seattle Options... 71 8.5 Risk Assessment Summary... 72 8.6 Intelligent Transportation Systems Summary... 73 9- REFERENCES... 75 9.1 South King County HCT Corridor Study... 75 9.2 Other Related Documents... 75 i
South King County High Capacity Transit Corridor Report LIST OF FIGURES Figure S-1. South King County Study Area... 1 Figure S-2. Level 2 Map of Alternatives... 5 Figure S-3. Level 2 Evaluation Results Summary... 6 Figure 1-1. Study Area... 2 Figure 1-2. Sound Transit Long-Range Plan... 3 Figure 3-1. PSRC and Local Centers... 13 Figure 3-2. Transit-Oriented Development Market Strength... 15 Figure 3-3. Socioeconomic Concentrations... 17 Figure 3-4. Travel Markets for Burien, Renton, Tukwila, and West Seattle... 21 Figure 3-5. Corridor Transit Routes by Service Tier... 23 Figure 3-6. Ring of Constraints into Downtown Seattle... 24 Figure 3-7. 2035 PM Peak Hour Congestion Levels... 26 Figure 3-8. Sidewalk Infrastructure... 27 Figure 3-9. Bicycle Infrastructure... 28 Figure 3-10. Other Infrastructure... 30 Figure 5-1. Initial Screening Process... 32 Figure 7-1. Primary Concepts Used In The Development Of Alternatives... 35 Figure 7-2. Level 1 Alternatives... 36 Figure 7-3. Level 1 Evaluation Summary... 42 Figure 7-4. Level 1 Downtown Seattle HCT Options... 45 Figure 8-1. Level 2 Alternatives... 47 Figure 8-2. Level 2 Evaluation Matrix... 51 ii
South King County High Capacity Transit Corridor Report LIST OF TABLES Table S-1. Sound Transit s HCT Goals and Objectives... 2 Table S-2. Alternatives Analyzed Under the Level 2 Evaluation... 4 Table 1-1. Sound Transit s HCT Goals and Objectives... 4 Table 3-1. Opportunities and Constraints... 11 Table 3-2. Top 5 Travel and Transit Markets... 20 Table 3-3. Existing Transit Route Tiers in the Corridor... 24 Table 4-1. Project Goals and Objectives... 31 Table 7-1. Level 1 Alternatives... 37 Table 7-2. Level 1 Evaluation Criteria... 40 Table 7-3. Alternatives Carried Forward to Level 2 Evaluation... 43 Table 8-1. Level 2 Evaluation Criteria... 48 Table 8-2. Findings - Downtown Seattle Options... 71 Table 8-3. Intelligent Transportation Systems Needs by Area... 74 Table 8-4. Intelligent Transportation Systems Needs by Level 2 Alternatives... 74 iii
South King County High Capacity Transit Corridor Report Executive Summary Figure S-1. South King County Study Area The South King County High Capacity Transit (HCT) Study is one of several HCT corridor planning studies Sound Transit has conducted to: Support the Sound Transit Board of Directors in decisions about the Sound Transit Long-Range Plan update, and; Inform choices for the next phase of the regional HCT system plan s development. The study area for the South King County HCT corridor (Figure S-1) encompasses Downtown Seattle, the SODO district, West Seattle, White Center and Burien, reaching east through SeaTac to Tukwila and Renton. Major travel routes in the study area include I-5, I-405, SR 99, SR 509 and SR 518. From a broad perspective, the corridor is characterized by strong transit markets fueled by supportive demographics, the presence of designated regional and local urban centers (these centers have been identified and adopted by PSRC, King County or local cities in their comprehensive plans), and focus towards Downtown Seattle. The corridor has several connecting points to existing light rail, commuter rail, and express bus service. Contributing to the mature transit market is a largely built-out land use pattern, although substantial population and employment growth is expected within the designated urban centers of Downtown Seattle, West Seattle, Burien, SeaTac, Tukwila, and Renton. This study identifies bus rapid transit and light rail corridor options that have potential to improve regional transit connections between Downtown Seattle, West Seattle, Burien, SeaTac, Tukwila and Renton. It evaluates at a conceptual-level the performance of ridership and mobility benefits, environmental effects and benefits, transit costs and cost-effectiveness, and consistency with regional and local plans. This is a conceptual-level study only. The cost estimates included here are conceptual and are intended for the purpose of comparison. A full environmental process would be required if and when any study corridors were to move forward Study Approach As shown in Table S-1, Sound Transit has developed a draft set of HCT guiding principles, goals and objectives for its Long-Range Plan update and supporting HCT corridor studies. These goals and objectives, as well as a statement of purpose and need for possible HCT improvement in the South King County Corridor helped form the evaluation criteria used to measure how effective potential improvements would be. This planning study is conceptual in nature and intended to outline a range of potential options to improve regional transit in the South King County Corridor. S-1
South King County High Capacity Transit Corridor Report Table S-1. Sound Transit s HCT Goals and Objectives Goal Objectives Provide a transportation system that facilitates long-term mobility Enhance communities and protect the environment Contribute to the region s economic vitality; increase access to jobs, housing, education, and other community resources; enhance the region s ability to move goods and services; and promote economic development Strengthen communities access to, and use of, the regional transit network Develop a system that is financially feasible Improve transit connections to key transit markets and regional growth centers Must operate service principally in exclusive rights-of- way to be considered as High- Capacity Transit Improve the reliability of transit service Conserve energy resources, control air pollution, and preserve the environment Support communities ability to develop sustainably, consistent with state and regional laws and growth management policies Support economic growth by linking the region s designated growth centers Support transit-oriented development in station areas Develop transit options that connect to existing and future bicycle, pedestrian, HOV, and transit networks Improve people s ability to access transit Develop equitable transportation solutions Develop cost-effective and efficient transportation solutions Develop a system that is affordable to build, run, and use Based on Sound Transit s current Long-Range Plan and previous studies, bus rapid transit (BRT) and light rail transit (LRT) were the primary modes considered for the South King County HCT corridor. These two modes of HCT have a fairly wide range of operating conditions. The following sections summarize the study process, the Level 1 and Level 2 evaluations along with the findings from the risk assessment and system integration analysis. S-2
South King County High Capacity Transit Corridor Report Study Process In this study, Sound Transit developed and evaluated potential high capacity transit improvements by initially screening BRT and LRT modes and a large range of alignments, followed by a two-level evaluation process to refine the options for more detailed examination. Sound Transit consulted with local jurisdictions and the Washington State Department of Transportation at key steps in this study. Initial screening evaluation - Reviewed a universe of options to connect designated centers within the corridor. Options were carried forward if they met the project goals and objectives. Initial Screening Evaluation Level 1 evaluation Evaluated 14 refined corridor alternatives based on the initial screening results. Alternatives were evaluated using performance measures set to meet the project goals and objectives. Level 1 Evaluation Level 2 evaluation - Refined the corridor alternatives based on the Level 1 results. More detailed and quantitative performance measures were used to assess the alternatives. Corridor Report - Summarized the study results and identified advantages and disadvantages for the Level 1 and 2 alternatives. Level 2 Evaluation Corridor Report Initial Screening Travel and transit market analysis data, along with land use, transportation and environmental information were used to develop a comprehensive set of options within the study corridors. The universe of options included potential modes and the communities that could be served. Each corridor option was screened against the goals and objectives. Potential options that did not adhere to the basic definition of HCT, that would be costly to build, or could have major construction challenges were screened out. The remaining options were combined and modified to create corridor alternatives carried forward to the Level 1 evaluation. Level 1 Evaluation Information from the baseline corridor analysis and the initial screening workshop was used to define three high-level conceptual corridor options, providing a range of options to best-serve travel demand in the corridor. From these three concepts, a total of 14 distinct alternatives were developed as part of the Level 1 evaluation. The alternatives included variations in routes (elevated, at-grade, and tunnel), technology/mode, and potential station area locations. Downtown Seattle alternatives warranted special consideration due to the complexities associated with existing and planned civil structures, infrastructure constraints, and integration with alternatives developed in the Ballard to Downtown Seattle Transit Expansion Study (Sound Transit, May 2014). Each alternative was then evaluated using the established performance measures including travel market S-3
South King County High Capacity Transit Corridor Report potential, environmental effects, regional growth center linkage, effects on the existing and planned transportation system, economic development, capital costs, and other metrics. The comparative evaluation identified the higher performing alternatives that were advanced to the Level 2 evaluation. Level 2 Evaluation Six alternatives were carried forward to the Level 2 evaluation as shown in Figure S-2 and Table S-2. Alternative C5 was a new alternative developed during the Level 1 evaluation workshop and subsequent analyses. Some of the alternatives were modified between the Level 1 and Level 2 evaluation processes, as described below. Table S-2. Alternatives Analyzed Under the Level 2 Evaluation Alternative Mode Description A3 A4 A5 B2 B4 LRT BRT LRT BRT LRT To Delridge, Burien/Renton. Modified to include a new, low moveable bridge across the Duwamish River. To Delridge, Burien/Renton. Modified to have more exclusivity across the West Seattle Bridge and on Delridge Way. To West Seattle with tunnel to White Center, Burien/Renton. Modified to add a new potential station area at the Fauntleroy/35 th /Alaska triangle. To White Center and Burien/Renton. Modified to have a more exclusive BRT facility to Burien. To White Center and Burien/Renton. Modified to add a new potential station area at the Fauntleroy/35 th /Alaska triangle. C5 LRT/BRT Rail to West Seattle and White Center; BRT Burien/Renton. Key Findings A summary of the Level 2 evaluation results is provided in Figure S-3. Subsequent pages describe each alternative and highlight the evaluation findings. The alternative alignments are described using the following terminology: o o o Exclusive= Elevated, tunnel, or off-street profile Semi-exclusive= At-grade with dedicated lanes Non-exclusive= At-grade within shared traffic lanes S-4
South King County High Capacity Transit Corridor Report Figure S-2. Level 2 Map of Alternatives S-5
Figure S-3. Level 2 Evaluation Results Summary South King County High Capacity Transit Corridor Report S-6
South King County High Capacity Transit Corridor Report Alternative A3 Alternative A3 is a light rail transit (LRT) alignment that travels via a mix of at-grade, elevated and tunnel profiles. It connects Downtown Seattle to West Seattle s Delridge Corridor, White Center, Top Hat, Burien, SeaTac, Tukwila and Renton. It includes a tunnel through Downtown Seattle, elevated segments through SODO and an at-grade profile through West Seattle and Burien. The alternative primarily follows SR-518 from Burien to Tukwila with at-grade, elevated and tunnel portions in SeaTac and Tukwila. From Tukwila to Renton, the alternative is a mix of elevated and at-grade profiles. Key findings: 47% exclusive and 53% semi-exclusive running way Serves the Delridge Corridor Higher ridership as compared to bus rapid transit (BRT) alternatives Moderate cost and engineering complexity as compared to other light rail alternatives Faster travel time between Burien and Downtown Seattle as compared to other alternatives due to a more direct travel path Does not directly serve the West Seattle Junction or Westwood-Highland Park urban villages Potential noise and visual effects due to surface alignment Complex connections between Tukwila International Boulevard Station and the Tukwila Sounder Station Lower ridership as compared to other light rail alternatives New low movable bridge across the Duwamish Waterway may impact freight operations and transit reliability Slower travel time between West Seattle and Downtown Seattle Total Ridership 63 to 77 K Travel Time: Seattle to Alaska Junction* 22-27 min Travel Time: Seattle to Burien Transit Center 24-30 min Travel Time: Seattle to Renton 37-46 min Capital costs only, with right-of-way** $4.6 - $6.1 B *Includes transfer to bus at Genesee/Delridge **Draft costs (2014$) shown are conceptual level estimates only and are used for purposes of comparison S-7
South King County High Capacity Transit Corridor Report Alternative A4 Alternative A4 is a BRT alignment that travels via a mix of at-grade and elevated profiles. It connects Downtown Seattle to West Seattle s Delridge Corridor, White Center, Top Hat, Burien, SeaTac, Tukwila and Renton. The Downtown Seattle portion is a one-way couplet along 4th and 5th Avenue while the SODO segment is via the existing E3 busway. The alternative crosses the Duwamish via the West Seattle Bridge and travels in dedicated and shared-use lanes through West Seattle to Burien. It travels in mixed traffic from Burien to Tukwila and in dedicated and shared-use lanes from Tukwila to Renton. Key Findings: Serves the Delridge Corridor Lowest expected noise and visual effects Low potential effects on the transportation system Lowest cost and engineering complexity 14% exclusive and 12% semi-exclusive running way Does not serve the West Seattle Junction or Westwood-Highland Park urban villages Lowest ridership potential Forecast demand may not be achievable due to capacity constraints Total Ridership 30 to 37 K Travel Time: Seattle to Alaska Junction 31-38 min Travel Time: Seattle to Burien Transit Center 41-50 min Travel Time: Seattle to Renton 70-86 min Capital costs only, with right-of-way* $1.9- $2.4 B *Draft costs (2014$) shown are conceptual level estimates only and are used for purposes of comparison S-8