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HomeMy WebLinkAboutEx14_Transportation_Impact_Analysis_-_Revised 6544 NE 61st Street Seattle, WA 98115 • 206-523-3939 • hefftrans.com TECHNICAL MEMORANDUM Project: Kennydale Gateway 4350 Lake Washington Boulevard N, Renton, WA Subject: Transportation Impact Analysis – REVISED Date: August 15, 2022 Author: Marni Heffron, P.E., P.T.O.E. This memorandum presents the transportation analysis for the Kennydale Gateway project located at 4350 Lake Washington Boulevard N in Renton, WA. This analysis was performed to be consistent with the City of Renton’s Traffic Impact Analysis Policy Guidelines for New Development.1 The analysis has been revised to address two rounds of comments—one from the City of Renton and one from its transportation review consultant.2 It includes a project description, estimate of project-generated trips, analysis of future traffic conditions in the site vicinity, and assessment of potential mitigation. The project program and site layout has changed slightly from the prior analyses, and the new program is reflected herein. This memorandum supersedes all prior analyses.3 As described in detail below, the project site is adjacent to the Interstate 405 (I-405) / NE 44th Street interchange, where the Washington State Department of Transportation (WSDOT) in partnership with Sound Transit will be constructing major improvements, which are described herein. WSDOT has performed extensive analysis of the interchange and nearby intersections and evaluated future 2025 and 2045 conditions. These future conditions had assumed more intensive development of the project site than is now contemplated. This transportation analysis presents trip generation estimates for the proposed development, and compares that to WSDOT’s analysis assumptions. 1. Project Description The 7.7-acre project site is bounded by Lake Washington Boulevard N on the west and north and I-405 and the southbound on-ramp to the east. The south edge of the site is a wooded public access corridor along the May Creek Trail. Figure 1 shows the site location and vicinity. 1 Provided by M. Herrera – City of Renton, October 8, 2020. 2 Comments from City of Renton, On Hold Notice from February 14, 2022; and comment from Transpo Group, July 20, 2022. 3 This memorandum supersedes prior memorandum: Heffron Transportation, Inc., Kennydale Gateway Transportation Analysis - Revised, June 14, 2021 and Heffron Transportation, Inc., Kennydale Gateway Transportation Analysis, September 9, 2019. EXHIBIT 14 RECEIVED Clark Close 08/15/2022 PLANNING DIVISION DocuSign Envelope ID: AB259DAD-E1F4-4927-9B6D-D48F19435899 Kennydale Gateway Transportation Impact Analysis – REVISED August 15, 2022 | 2 Figure 1. Site Location Source of Aerial: GoogleEarth, July 2022. The project proposes to develop 385 apartment units and parking for 385 vehicles. One of the buildings (Building 1) would also include a 1,500 square foot (sf) ground-floor commercial retail space near the development’s entrance on Lake Washington Boulevard N. The proposed Kennydale Gateway project is expected to be completed and occupied in the 3rd quarter of 2025. The site would have one access point for residential and commercial traffic via a driveway on Lake Washington Boulevard NE opposite NE 43rd Street. The project would construct a roundabout at this intersection, which was envisioned in WSDOT’s plans for the area, and which are described later in this report. An emergency-only access driveway would be located at the south edge of the site, and would have bollards or other treatment to prevent general- vehicle use. WSDOT’s right-of-way for I-405 borders the east edge of the site and WSDOT will construct a retaining wall west of the on-ramp. Because WSDOT’s new interchange would be constructed under I- 405 and the grade of NE 44th Street would change, the roundabout at the site access would be the closest pedestrian access point to the interchange. Figure 2 shows the propsoed site plan. SITE DocuSign Envelope ID: AB259DAD-E1F4-4927-9B6D-D48F19435899 Kennydale Gateway Transportation Impact Analysis – REVISED August 15, 2022 | 3 Figure 2. Kennydale Gateway Site Plan Source: HLR Architects, August 2022 N DocuSign Envelope ID: AB259DAD-E1F4-4927-9B6D-D48F19435899 Kennydale Gateway Transportation Impact Analysis – REVISED August 15, 2022 | 4 2. Future Transportation Improvements WSDOT is planning major improvements as part of the I-405, Tukwila to I-90 Vicinity Express Toll Lanes Project (Tukwila to I-90 Project). A segment of the overall corridor project, known as the “I- 405/Renton to Bellevue Widening and Express Toll Lanes Project” is currently under construction. The current schedule predicts that the project will be complete and open to traffic in Fall 2024.4 In general, WSDOT’s Renton-to-Bellevue project proposes to add one lane to I-405 in each direction for about nine miles beginning near State Route (SR) 167 and continuing approximately one mile north of Interstate 90 (I-90). The project would also add a general-purpose (auxiliary) lane to southbound I-405 between milepost (MP) 6.7 (north of N 30th Street) and MP 7.1 (south of NE 44th Street) and from MP 9.4 (north of 112th Avenue SE) to MP 10.5 (north of Coal Creek Parkway). The existing high-occupancy vehicle (HOV) lane on I-405 and the additional auxiliary lane would be operated as a two-lane express toll lane system.5 WSDOT will also rebuild the I-405 / NE 44th Street interchange. The current plan, which is under con- struction, will relocate NE 44th Street / Lake Washington Boulevard N to pass under I-405. On the west side of I-405, regrading will begin at about N 43rd Street, and the grade of the street at Seahawk’s Way will be lowered by about 7 feet compared to the current overpass condition. The new interchange will also have HOV-only ramps from the center lanes of I-405 and a Bus Rapid Transit (BRT) station ac- cessed from those ramps (Sound Transit is a funding partner for the interchange improvements to sup- port new BRT service on I-405, which is described later). Figure 3 shows a concept of the interchange, which includes the following features. • The northbound ramps, southbound ramps, and direct HOV ramps will be controlled by rounda- bouts where they intersect Lake Washington Boulevard N and NE 44th Street. • The WSDOT analysis also contemplated that the intersection at the Lake Washington Boulevard N / N 43rd Street intersection, at which a new east leg would serve as the site access for the Kennydale Gateway project, would be controlled with a roundabout that would be built by others. The Kennydale Gateway project proposes to construct this roundabout. • The intersection at Lake Washington Boulevard N / Seahawks Way will be reconfigured to prohibit all left turn movements. Turns from Seahawks Way will be stop-sign controlled. Prohibited move- ments would proceed to adjacent roundabouts to reverse direction.6 It is noted that WSDOT had originally assumed that the site would have a secondary access connecting to the south leg of the Seahawks Way intersection. However, that access is no longer proposed. 4 WSDOT project website, https://wsdot.wa.gov/construction-planning/search-projects/i-405renton-bellevue-widening-and- express-toll-lanes-project, accessed July 25, 2022. 5 WSDOT, Transportation Discipline Report: I-405, Tukwila to I-90 Vicinity Express Toll Lanes Project (MP 0.0 to 11.9) and Downtown Bellevue Vicinity Express Toll Lanes Project (MP 11.9 to 14.6), July 2018. 6 Based on geometric and traffic control assumptions in WSDOT’s Synchro model for this intersection, HNTB, filename: 2025Build.AM.syn, October 2016. DocuSign Envelope ID: AB259DAD-E1F4-4927-9B6D-D48F19435899 Kennydale Gateway Transportation Impact Analysis – REVISED August 15, 2022 | 5 Figure 3. Concept Plan for Future I-405 / NE 44th Street Interchange Source: WSDOT and Flatiron Lane, Image from Sound Transit presentation, July 2021. Sound Transit is helping to fund some of the improvements along the I-405 corridor and at the NE 44th Street interchange to support its voter-approved Bus Rapid Transit (BRT) corridor, known as Stride. The S1 line between Burien and Bellevue is currently anticipated to begin operating in 2026 or 2027.7 The 44th Street BRT Station is being constructed as part of the WSDOT improvements described above. The Sound Transit Board voted to defer a new 200-space park-and-ride lot until 2034 as part of its funding realignment process.8 Originally, the park-and-ride lot had been contemplated to be located on the Ken- nydale Gateway site, but that is no longer proposed, and an alternative site has not yet been selected. Given available land in the area, the future station is likely to be located on the east side of I-405. Because the WSDOT interchange improvements and BRT Station are funded, all analyses herein reflect their completion for future conditions. No analysis of the existing roadway system was performed. 7 Sound Transit website: https://www.soundtransit.org/system-expansion/i-405-brt/timeline-milestones, accessed July 25, 2022. 8 Sound Transit news release, September 2021. https://www.soundtransit.org/get-to-know-us/news-events/news- releases/sound-transit-board-selects-stride-brt-projects-to-be DocuSign Envelope ID: AB259DAD-E1F4-4927-9B6D-D48F19435899 Kennydale Gateway Transportation Impact Analysis – REVISED August 15, 2022 | 6 3. Site Trips 3.1. Trip Generation A new edition of the Institute of Transportation Engineers’ (ITE) Trip Generation Manual9 was released after the original TIA for this project was completed. Trip generation rates and equations in the new ver- sion were used for this revised TIA. The following describes the trip assumptions applied for each of the land uses. • Apartments – There are many different trip rates in the new edition of the Trip Generation Man- ual for multifamily uses, which vary based on the neighborhood and transit context. For this study, data for “Multifamily Housing (Mid-Rise) Not Close to Rail Transit” in a General Urban/Suburban setting were used. Even though the project site will be close to the future Stride BRT Station, no adjustments were made to reflect potential higher use of transit by residents. • Commercial Retail – The small retail space on the site (about 1,500 sf) has no known tenant and is not being designed to accommodate restaurant functions. Therefore, rates and equations for a new retail sub-category in the Trip Generation Manual specifically for small retail—“Strip Retail Plaza (<40k)”—were applied. No adjustments for internal trips between this use and the residen- tial use were assumed and no adjustments for transit use were made. The trip equations and rates applied for this analysis are listed in Table 1. Table 1. Trip Generation Rates, Equations, and Vehicle Trip Adjustments Land Use / Definition Trip Generation Rates and Equations 1 Multifamily Housing (Mid-rise), Not Close to Rail Transit in a General Urban/Suburban Setting (ITE Land Use Code 221) – Includes apartments, townhouses, and condominiums located with the same building with at least three other dwell- ing units and that have between three and 10 levels (floors). Equations for a “General Urban/Suburban” setting were used. Daily 2 T = 4.77(X) - 46.46(50% in, 50% out) AM Peak Hour of Adjacent Street 2 T = 0.44(X) - 11.61(23% in, 77% out) PM Peak Hour of Adjacent Street 2 T = 0.39(X) + 0.34(61% in, 39% out) Strip Retail Plaza (<40k) (LU 822) – Integrated group of commercial establishments that is planned, developed, owned, and managed as a unit, less than 40,000 square feet of gross leasable area. Daily 2 T = 42.20(X) + 229.68 (50% in, 50% out) AM Peak Hour of Adjacent Street 3 2.36 trips/1,000 sf(50% in, 50% out) PM Peak Hour of Adjacent Street 2 Ln(T) = 0.71Ln(X) +2.72(50% in 50% out) 1. Institute of Transportation Engineers (ITE) Trip Generation, 11th Edition, September 2021. For residential equations, T = number of trips, X = number of dwelling units; for commercial rates, “sf” = square feet. 2. Per guidance in the ITE Trip Generation Handbook, 3rd Edition, September 2017, fitted curve equations were used since the number of data points exceeds 20 and/or the equation’s R-squared value is equal to or greater than 0.75. 3. Average rate was applied per guidance ITE Trip Generation Handbook, 3rd Edition, September 2017. Vehicle trips were estimated using the rates and equations listed above. The resulting vehicle trip esti- mates are summarized in Table 2. As shown, the site is expected to generate an estimated 2,080 vehicle trips per day with 162 trips during the AM peak hour and 170 trips during the PM peak hour. 9 ITE, 11th Edition, September 2021. DocuSign Envelope ID: AB259DAD-E1F4-4927-9B6D-D48F19435899 Kennydale Gateway Transportation Impact Analysis – REVISED August 15, 2022 | 7 Table 2. Vehicle Trips Generated by Site Daily Trips AM Peak Hour Trips PM Peak Hour Trips Land Use Proposed Size In Out Total In Out Total Apartments 385 units 1,790 41 117 158 92 58 150 Commercial Use 1,500 sf 290 2 2 4 10 10 20 Total Site 2,080 43 119 162 102 68 170 Source: Heffron Transportation, Inc., August 2022. Applied trip generation rates and vehicle adjustments presented in Table 1. 3.2. Trip Distribution and Assignment A trip distribution pattern for the development site was derived based on WSDOT’s 2025 traffic volume forecasts. About 60% of the site traffic is expected to use the I-405 general-purpose lanes (40% to/from the north and 20% to/from the south) with a small percentage using the HOV direct access ramps (5% to/from the north and 2% to/from the south). A small amount of traffic was assumed to be destined to or from areas south of the site along Lake Washington Boulevard where several parks are located. The rest would be destined to areas east of I-405 where the neighborhood’s schools and services are located. The project trips were assigned to the roadway network based on this pattern. Figure 4 shows the trip distri- bution pattern and peak hour trip assignments (AM and PM peak hours). DocuSign Envelope ID: AB259DAD-E1F4-4927-9B6D-D48F19435899 Project Site Lake Washington Blvd NN 4 1 s t S t d405 Seahawks WayNorthbound On-Ramp N 43rd St HOV Ramp one way one way 1(5) 42 (97) 117 (65) 2 (3) 117(65) 42 (97) (41) 14 (51) 93 25 (56) (14) 24 48 (27) (14) 6 15 (10) 9 (20) (14) 6 (10) 22 7 (15) (37) 63 1 (2) (5) 2 (47) 85 22 (49) (1) 2 (3) 6 1 (5) 2 (3) 20% +2% HOV 40% +5% HOV 5%15% 13% KEY ##%Trip Distribution Study Intersection Peak Hour Trips:Future Roundabout ##AM Peak Hour Future Bus Rapid Transit (BRT) Station(##)PM Peak Hour Figure 4 Trip Distribution Pattern and Project Trips KENNYDALE GATEWAY N DocuSign Envelope ID: AB259DAD-E1F4-4927-9B6D-D48F19435899 Kennydale Gateway Transportation Impact Analysis – REVISED August 15, 2022 | 9 4. Year 2025 Traffic Volumes WSDOT, through its consultant HNTB, performed extensive analysis of the improvements now under construction at the NE 44th Street interchange. It evaluated future conditions without and with the im- provements for the years 2025 and 2045. The year 2025 traffic volumes were used for this analysis since the new interchange and the Kennydale Gateway project would be complete by that year. The full corridor growth assumptions were provided in the Transportation Discipline Report: I-405, Tukwila to I-90 Vicinity Express Toll Lanes Project (MP 0.0 to 11.9) and Downtown Bellevue Vicinity Express Toll Lanes Project (MP 11.9 to 14.6).10 Additional detail was provided in the companion I-405 Renton to Bellevue – NE 44th Street Intersection Control Analysis Report.11 WSDOT also provided both the SIDRA software files (used to evaluate roundabouts) and Synchro software files (used to evaluate the intersection at Lake Washington Boulevard N / Seahawks Way), and these models included the assump- tions related to intersection geometry and turning movement values.12 WSDOT’s operating assump- tions, including volume-to-capacity (v/c) ratios, were retained from those models. According to WSDOT,13 its 2025 traffic volume forecasts assumed traffic generated by three major developments plus background growth. The three developments were: • The Port Quendall Terminals development located on the north side of Lake Washington Boulevard N between N 43rd Street and Seahawks Way; • The Hawk’s Landing development located on the south side of Lake Washington Boulevard N between the southbound I-405 on-ramp and N 43rd Street; and • The Kennydale Mixed-Use development located on the south and east side of Lake Washington Boulevard N. The last development listed above is the development originally anticipated for the subject Kennydale Gateway site. The numbers of trips assumed to be generated by the subject site in the WSDOT analysis were derived from the traffic operations models. The WSDOT analysis had assumed that the site would have two access driveways: the primary driveway was assumed to be a right-in/right-out only onto Lake Washington Boulevard N opposite Seahawks Way at the northwest corner of the site, a second access was assumed to connect to the proposed roundabout at N 43rd Street. The numbers of peak hour trips assumed in WSDOT’s 2025 models are summarized in Table 3; the estimates prepared for the current proposal and described previously are included for comparison. As shown, the current proposal is ex- pected to generate fewer trips than had already been assumed in the WSDOT analysis (159 fewer trips in the AM peak hour and 153 fewer trips in the PM peak hour). 10 WSDOT, July 2018. 11 WSDOT, July 2018. 12 WSDOT/HNTB Sidra and Synchro models for year 2025 build (with interchange improvement) conditions. 13 E-mail from Sean Quarrie of WSDOT to Marni Heffron, Heffron Transportation, March 8, 2019. DocuSign Envelope ID: AB259DAD-E1F4-4927-9B6D-D48F19435899 Kennydale Gateway Transportation Impact Analysis – REVISED August 15, 2022 | 10 Table 3. Comparison of Kennydale Gateway Site Trips to WSDOT Assumed Condition AM Peak Hour Trips PM Peak Hour Trips Analysis Condition In Out Total In Out Total Assumed by WSDOT in its 2025 Models 1 166 155 321 150 173 323 Updated Estimate for Site (see Table 2) 43 119 162 102 68 170 Net Difference -123 -36 -159 -48 -105 -153 1. Determined from WSDOT / HNTB Sidra and Synchro models for year 2025 build (with interchange improvement) conditions. WSDOT’s year 2025 traffic volumes were adjusted to reflect the changed development assumptions for the Kennydale Gateway site as well as the elimination of the site driveway opposite Seahawks Way that WSDOT had included in its analysis. First, all of the site trips assumed for the site were subtracted from the network. Since WSDOT did not provide detail about its assumptions related to trip patterns, the 2025 trip patterns through the interchange were used to derive it. The assumed trip reductions are shown in Attachment A. Next, the Kennydale Gateway trips shown on Figure 4 were added to the system. Figure 5 and Figure 6 show the revised 2025 traffic volumes with the currently-proposed Kennydale Gateway project for the AM and PM peak hours, respectively. DocuSign Envelope ID: AB259DAD-E1F4-4927-9B6D-D48F19435899 Project Site Lake Washington Blvd NN 4 1 s t S t d405 Seahawks WayNorthbound On-Ramp N 43rd St HOV Ramp one way one way 40 750 1 15 186 42 117 0 2 335 0 50 1202 110 233 10 268 52 45 0 1109 298 93 85 35 496 45 37 13 382 13 365 259 29 45 130 423 286 276 60 579 152 95 21 28 112 60 0 725 481 0 38 398 2 787 1 237 4 2 KEY Study Intersection Future Roundabout Future Bus Rapid Transit (BRT) Station Figure 5 Year 2025 Traffic Volumes With Kennydale Gateway AM Peak Hour KENNYDALE GATEWAY N DocuSign Envelope ID: AB259DAD-E1F4-4927-9B6D-D48F19435899 Project Site Lake Washington Blvd NN 4 1 s t S t d405 Seahawks WayNorthbound On-Ramp N 43rd St HOV Ramp one way one way 70 218 5 50 533 97 65 0 3 223 0 30 506 345 660 20 260 78 203 20 424 802 82 67 36 172 53 98 10 699 10 451 123 35 70 140 696 216 369 220 378 188 35 28 66 172 157 0 356 877 0 54 92 5 286 4 562 7 4 KEY Study Intersection Future Roundabout Future Bus Rapid Transit (BRT) Station Figure 6 Year 2025 Traffic Volumes With Kennydale Gateway PM Peak Hour KENNYDALE GATEWAY N DocuSign Envelope ID: AB259DAD-E1F4-4927-9B6D-D48F19435899 Kennydale Gateway Transportation Impact Analysis – REVISED August 15, 2022 | 13 5. Traffic Operations 5.1. NE 44th Street / I-405 Interchange Analysis Levels of service (LOS) for intersections at and near the NE 44th Street interchange were determined us- ing WSDOT’s SIDRA and Synchro traffic operations models provided by WSDOT and described earlier. Level of service, is a measure of congestion, with LOS A reflecting good operations with little to no congestion and LOS F, reflecting poor operations with substantial congestion. While WSDOT had no targeted level of service standard for the I-405 corridor improvements, the WSDOT Level of Service Standard Map14 indicates LOS D is the standard for I-405. Analysis of the unsignalized intersections were performed using the Synchro 10.3 traffic operations analysis software and reported using the Highway Capacity Manual, 6th Edition (HCM 6) module. The roundabout intersections were evaluated using the Sidra 9 software’s Network analysis module and reporting methodology. The SIDRA analyses reflect model coding parameters established in the WSDOT Sidra Policy Settings,15 and no changes to WSDOT’s assumed operating parameters or v/c ratios were made. software’s Network analysis module and reporting methodology. The level of service definitions and thresholds are provided in Attachment B. Table 4 summarizes forecast intersection operations for year 2025 conditions with the Kennydale Gate- way project. Adjustments were made to the models at the Seahawks Way and N 43rd Street intersections to remove the previously assumed secondary access for the Kennydale Gateway site at Seahawks Way. All access to that site is now proposed to occur at N 43rd Street. As shown, all of the proposed intersec- tions are expected to operate at good levels of service (LOS B or better) in the year 2025 with the pro- posed interchange configuration and the Kennydale Gateway project. The results from the analysis are consistent with those reported in the WSDOT’s I-405 Renton to Bellevue – NE 44th Street Intersection Control Analysis Report. Table 4. Intersection Level of Service – Year 2025 conditions With Volumes Assumed by WSDOT a Intersection Proposed Control AM Peak Hour PM Peak Hour Lake Wash Blvd N / N 43rd St / Site Access Roundabout B A Lake Washington Boulevard N / Seahawks Way Stop signs on Seahawks Wy / Stop Sign /No left turns allowed A A NE 44th St / SB Off and On Ramps Roundabout A A NE 44th St / HOV Ramp Roundabout A A NE 44th St / NB Off Ramp Roundabout A A Lake Wash Blvd N / NB On-Ramp Roundabout A A Source: Heffron Transportation, Inc., August 2022. Year 2025 SIDRA and Synchro files provided by WSDOT were used. Roundabouts evaluated using software’s Network analysis module and reporting methodology. The SIDRA analyses reflect model coding parameters established in the WSDOT Sidra Policy Settings 14 WSDOT Level of Service Map, https://wsdot.maps.arcgis.com/home/item.html?id=3f840aeeb1ba481c905270ca103cd1db#!, accessed July 25, 2022. 15 WSDOT, https://wsdot.wa.gov/sites/default/files/2021-03/TrafficOps-WSDOTSidraPolicyAndSettings.pdf, accessed March 2022. DocuSign Envelope ID: AB259DAD-E1F4-4927-9B6D-D48F19435899 Kennydale Gateway Transportation Impact Analysis – REVISED August 15, 2022 | 14 WSDOT’s Transportation Discipline Report also assessed year 2045 conditions with the proposed im- provements. That analysis showed that all of the roundabouts would continue to operate at LOS A in both the AM and PM peak hour conditions. The WSDOT analysis had assumed that the stop-controlled inter- section at Lake Washington Boulevard N / Seahawks Way would degrade by 2045 to LOS C in the AM peak hour and LOS B in the PM peak hour, but that analysis assumed a driveway to the park-and-ride. Without either the park-and-ride or that driveway, this intersection would also operate at LOS A in 2045. The LOS calculations sheets are included in Attachment C. 5.2. Intersection at N 41st Street / Lake Washington Boulevard N The City of Renton requested analysis of the N 41st Street / Lake Washington Boulevard N intersection in its March 2021 comments. This intersection is located south of the Kennydale Gateway site. N 41st Street becomes Wells Avenue N just west of the intersection. This street is one of three access routes to the Barbee Mill residential development to the west. That development can also access Lake Washing- ton Boulevard further north at N 43rd Street and further south at N 37th Street. New turning movement counts were performed at the N 41st Street / Lake Washington Boulevard N intersection on Tuesday, March 1, 2022. A count on Wells Avenue N, performed on October 24, 2019, was used to adjust the side-street volumes to reflect non-pandemic conditions. It is noted that both sets of counts show relatively low volumes entering and exiting the residential area via N 41st Street, likely due to the fact that there are alternative development access points both north and south of N 41st Street. Figure 5 and Figure 6 (presented previously) show the year 2025 traffic volume forecasts with the Ken- nydale Gateway project for the AM and PM peak hours, respectively. It is noted that WSDOT’s 2025 forecasts reflected substantial growth in through traffic on Lake Washington Boulevard compared to 2021 conditions. For example, AM peak period traffic is estimated to increase from the year-2021 level of about 520 vehicles per hour (vph) (total in both directions) to over 1,020 vph by 2025, which is nearly a 200% increase. Likewise, PM peak period traffic was estimated to increase from about 460 vph to about 860 vph by 2025 (about 186% higher). Levels of service for the intersection were determined based on methodologies established in the High- way Capacity Manual (HCM), 6th Edition16 using the Synchro 10.3 analysis software. The existing inter- section has a single approach lane on all three legs with a stop sign controlling eastbound traffic. There are bike lanes in both directions and a trail crossing N 41st Street west of the intersection. The existing speed limit on Lake Washington Boulevard N is posted at 25 mph. The traffic volumes described above along with the peak hour factors, pedestrian, bicycle, and heavy-vehicle attributes based on the new counts were inputs to the model. The analysis determined that eastbound movements from the stop sign are expected to operate at LOS C in 2025 during both peak hours even with the substantial increases in traffic on Lake Washington Boule- vard N. The Kennydale Gateway project would not change the levels of service, and is expected to in- crease delay by a negligible amount (0.1 second added average delay per vehicle or less). Based on this analysis, the project is not expected to adversely affect the 41st Street / Lake Washington Boulevard N intersection. The LOS calculations sheets are included in Attachment C. 16 Transportation Research Board 2016. DocuSign Envelope ID: AB259DAD-E1F4-4927-9B6D-D48F19435899 Kennydale Gateway Transportation Impact Analysis – REVISED August 15, 2022 | 15 5.3. Future Roundabout at Lake Washington Blvd N / N 43rd Street WSDOT’s NE 44th Street interchange improvements contemplate a future roundabout at the Lake Washington Boulevard N / N 43rd Street / Site Access intersection to be built by others. The roundabout configuration that WSDOT assumed had two lanes on each of the major Lake Washington Boulevard N approaches, and one lane each on the minor N 43rd Street and the Site Access approaches. As previously noted, the WSDOT analysis had assumed a 200-stall park-and-ride lot on the site with a right-in/right-out only driveway on Lake Washington Boulevard N opposite Seahawks Way. The cur- rent proposed Kennydale Gateway site plan would have neither the park-and-ride lot nor this driveway. All site-generated traffic would arrive and depart the site through the roundabout at N 43rd Street. Because the site generated volumes and access would differ from the prior WSDOT analysis, future operations for a roundabout at Lake Washington Boulevard N / N 43rd Street / Site Access were evalu- ated. It was determined that a single-lane roundabout (one approach lane in all directions) would operate at LOS B during the AM peak hour and LOS A during the PM peak hour with the proposed project. In both the AM and PM peak hours, calculated 95th-percentile queue lengths do indicate any issues with queue spillback into surrounding intersections. The project proposes to construct a single-lane roundabout at this intersection. The LOS and queueing calculations sheets are included in Attachment C. 6. Summary The proposed Kennydale Gateway site is expected to generate an estimated 2,080 vehicle trips per day with 162 trips during the AM peak hour and 170 trips during the PM peak hour. More traffic had been assumed by WSDOT in its plans and analysis for future improvements at the NE 44th Street interchange with I-405. The substantial upgrade to this interchange, which will replace the existing freeway overpass with an under-crossing, add a direct access ramp connection to the I-405 HOV lanes, and replace ramp junction intersections with roundabouts is expected to operate very well in the future. Analysis determined that the proposed ramp intersections would operate at LOS A in the year 2025 and beyond with growth associated with the Kennydale Gateway and other local projects. The project is not expected to adversely affect the 41st Street / Lake Washington Boulevard N intersection. The project would construct a single-lane roundabout at the Lake Washington Boulevard N / N 43rd Street / Site Access intersection. This roundabout is expected to operate at LOS B during the AM peak hour and LOS A during the PM peak hour. No further mitigation would be needed to accommodate the project. Attachments: Attachment A - Year 2025 Traffic Volume Backup Attachment B – Level of Service Definitions Attachment C – Level of Service Calculations for Site Driveway Intersection MCH/tsm Kennydale Gateway Traffic Impact Analysis - REVISED - 08-15-2022 DocuSign Envelope ID: AB259DAD-E1F4-4927-9B6D-D48F19435899 DocuSign Envelope ID: AB259DAD-E1F4-4927-9B6D-D48F19435899 Attachment A Year 2025 Traffic Volume Backup DocuSign Envelope ID: AB259DAD-E1F4-4927-9B6D-D48F19435899 Project Site Lake Washington Blvd NN 4 1 s t S t d405 Seahawks WayNorthbound On-Ramp N 43rd St HOV Ramp one way one way 40 757 25 15 186 134 13 0 25 335 0 50 1098 7 110 325 117 10 268 52 78 0 1133 358 82 85 35 485 45 37 13 395 13 368 259 30 45 130 435 291 287 60 571 152 95 38 28 112 83 0 722 505 0 48 415 KEY Study Intersection Future Roundabout Future Bus Rapid Transit (BRT) Station Figure A-1 Year 2025 Traffic Volumes From WSDOT Analysis AM Peak Hour thSource: WSDOT, I-405 Renton to Bellevue – NE 44 Street Intersection Control Report, June 2018, Figure A4. Year 2025 Build Peak Hour Turning Movements KENNYDALE GATEWAY N DocuSign Envelope ID: AB259DAD-E1F4-4927-9B6D-D48F19435899 Project Site Lake Washington Blvd NN 4 1 s t S t d405 Seahawks WayNorthbound On-Ramp N 43rd St HOV Ramp one way one way 70 223 20 50 533 120 14 0 24 223 10 30 455 5 135 20 260 78 212 20 500 821 90 67 36 185 53 98 10 703 10 462 123 20 70 140 700 232 372 220 402 188 35 38 66 172 174 0 396 869 0 67 115 5 345 683 KEY Study Intersection Future Roundabout Future Bus Rapid Transit (BRT) Station Figure A-2 Year 2025 Traffic Volumes From WSDOT Analysis PM Peak Hour thSource: WSDOT, I-405 Renton to Bellevue – NE 44 Street Intersection Control Report, June 2018, Figure A4. Year 2025 Build Peak Hour Turning Movements KENNYDALE GATEWAY N DocuSign Envelope ID: AB259DAD-E1F4-4927-9B6D-D48F19435899 Project Site Lake Washington Blvd NN 4 1 s t S t d405 Seahawks WayNorthbound On-Ramp N 43rd St HOV Ramp one way one way -25 (-20) -134 (-120) -13 (-15) -25 (-24) -13(-14) 0 (-5) (-50) -50 (-127) -84 (-75) (-22) -20 -36 (-40) (-18) -18 -18 (-21) -10 (-5) (-18) -18 (-26) -21 -18 (-18) (-61) -54 -13 (-12) (-22) -25 (-87) -75 -46 (-41) (-14)-12 (-26) -23 -7(-5) -7(-5) -134 (-120) -117 (-135) -110 -32 (-25) -24 (-25) KEY Peak Hour Trips:Study Intersection ##AM Peak Hour Future Roundabout (##)PM Peak Hour Future Bus Rapid Transit (BRT) Station Figure A-3 Site Trips Removed From WSDOT 2025 Traffic Volumes REMOVED TRIPS IN OUT AM PEAK 166 155 PM PEAK 150 173 KENNYDALE GATEWAY N DocuSign Envelope ID: AB259DAD-E1F4-4927-9B6D-D48F19435899 Attachment B Level of Service Definitions DocuSign Envelope ID: AB259DAD-E1F4-4927-9B6D-D48F19435899 Appendix – Level of Service Definitions August 15, 2022 | B-1 Stop-Controlled Intersections For unsignalized stop-controlled intersections, level of service is based on the average delay per vehicle for each turning movement. The level of service for all-way stop-controlled intersections is based upon the average delay for all vehicles that travel through the intersection. The level of service for a one- or two- way, stop-controlled intersection, delay is related to the availability of gaps in the main street's traffic flow, and the ability of a driver to enter or pass through those gaps. Table B-1 shows the level of service criteria for unsignalized intersections from the Highway Capacity Manual, Sixth Edition. Table B-1. Level of Service Criteria for Unsignalized Intersections Level of Service Average Control Delay per Vehicle A 0 – 10 seconds B > 10 – 15 seconds C > 15 – 25 seconds D > 25 – 35 seconds E > 35 – 50 seconds F > 50 seconds Source: Transportation Research Board, Highway Capacity Manual, Exhibit 20.2, 2016. Roundabout-Controlled Intersections Using SIDRA Method The Washington State Department of Transportation (WSDOT) Sidra Policy Settings17 recommends reporting roundabout operations using the SIDRA Site LOS Method. This method bases the LOS on both delay and degree of saturation (volume-to-capacity (V/C) ratio). The LOS criteria and thresholds are provided in Table B-3. The delay and V/C (HCM 6) method could be considered a simplified version of this method as it reports LOS F for oversaturated conditions (V/C > 1.0), but the SIDRA method applies V/C ratios that can result in LOS D or E for degrees of saturation close to 1.0. The results presented in this report reflect the SIDRA Site LOS Method, but consider the HCM 6.0 guidance as follows: • the v/c ratio (degree of saturation) is taken into account together with the average delay value in determining LOS for lanes and movements, but • only the average delay value is considered in determining LOS for approaches and the intersection. Table B-3. Delay & Degree of Saturation (SIDRA) Level of Service Definitions for Roundabout Intersections Average Control Delay Per Vehicle Level of Service Approaches and Intersections (overall) Individual Movements Degree of saturation (V/C ratio of movements) A ≤ 10 seconds 0 – 10 seconds ≤ 0.85 B > 10 – 20 seconds > 10 – 20 seconds ≤ 0.85 C > 20 – 35 seconds > 20 – 35 seconds ≤ 0.85 D > 35 – 55 seconds > 30 – 50 seconds > 0 – 50 seconds ≤ 0.85 > 0.85 – ≤ 0.95 E > 55 – 80 seconds > 50 – 70 seconds > 0 – 70 seconds ≤ 0.95 > 0.95 – ≤ 1.00 F > 80 seconds > 70 seconds > 1.00 Source: SIDRA Solutions, SIDRA 9.0 Analysis Method (based on a proposal by Berry, 1987). Only the average delay value is considered in determining LOS for approaches and the intersection. 17 WSDOT, https://wsdot.wa.gov/sites/default/files/2021-03/TrafficOps-WSDOTSidraPolicyAndSettings.pdf, accessed Mar. 2022. DocuSign Envelope ID: AB259DAD-E1F4-4927-9B6D-D48F19435899 Attachment C Level of Service Calculations for Site Access Intersection DocuSign Envelope ID: AB259DAD-E1F4-4927-9B6D-D48F19435899 USER REPORT FOR NETWORK SITE All Movement Classes Project: 44th_Five Roundabout_Build_Option 2_2025 - REVISED August 2022 HTi Template: Movement Report for Appendix Site: 1 [NE 44th St and NE 43rd St-AM (Site Folder: General)] Network: 1 [Renton-to-Bellevue: Year 2025 NE 44th Street AM (Network Folder: General)] New Site Site Category: (None) Roundabout Vehicle Movement Performance DEMAND FLOWS ARRIVAL FLOWS 95% BACK OF QUEUE Mov ID Turn Deg. Satn Aver. Delay Level of Service Prop. Que Effective Stop Rate Aver. No. Cycles Aver. Speed [ Total HV ][ Total HV ][ Veh.Dist ] veh/h %veh/h %v/c sec veh ft mph South: 43rd Driveway 3 L2 2 3.0 2 3.0 0.328 18.8 LOS B 2.6 65.9 1.00 0.98 1.00 26.2 8 T1 1 3.0 1 3.0 0.328 13.2 LOS B 2.6 65.9 1.00 0.98 1.00 26.0 18 R2 123 3.0 123 3.0 0.328 13.7 LOS B 2.6 65.9 1.00 0.98 1.00 22.0 Approach 126 3.0 126 3.0 0.328 13.8 LOS B 2.6 65.9 1.00 0.98 1.00 22.1 East: 44th 1 L2 44 3.0 44 3.0 0.198 7.3 LOS A 1.3 32.8 0.22 0.35 0.22 29.2 6 T1 196 3.0 196 3.0 0.198 2.2 LOS A 1.3 32.8 0.22 0.35 0.22 28.9 16 R2 16 3.0 16 3.0 0.198 2.7 LOS A 1.3 32.8 0.22 0.35 0.22 27.8 Approach 256 3.0 256 3.0 0.198 3.1 LOS A 1.3 32.8 0.22 0.35 0.22 28.9 North: 43rd Driveway 7 L2 353 3.0 353 3.0 0.359 8.5 LOS A 2.1 52.8 0.46 0.64 0.46 24.8 4 T1 1 3.0 1 3.0 0.359 3.3 LOS A 2.1 52.8 0.46 0.64 0.46 27.7 14 R2 53 3.0 53 3.0 0.359 3.8 LOS A 2.1 52.8 0.46 0.64 0.46 27.1 Approach 406 3.0 406 3.0 0.359 7.8 LOS A 2.1 52.8 0.46 0.64 0.46 25.3 West: 44th 5 L2 42 3.0 42 3.0 0.856 18.1 LOS D 15.3 390.6 1.00 1.18 1.51 26.6 2 T1 789 3.0 789 3.0 0.856 12.5 LOS D 15.3 390.6 1.00 1.18 1.51 22.6 12 R2 1 3.0 1 3.0 0.856 13.5 LOS D 15.3 390.6 1.00 1.18 1.51 25.7 Approach 833 3.0 833 3.0 0.856 12.8 LOS B 15.3 390.6 1.00 1.18 1.51 22.9 All Vehicles 1621 3.0 1621 3.0 0.856 10.1 LOS B 15.3 390.6 0.74 0.89 1.00 24.4 Site Level of Service (LOS) Method: Delay & Degree of Saturation (SIDRA). Site LOS Method is specified in the Network Data dialog (Network tab). Roundabout LOS Method: Same as Signalised Intersections. Vehicle movement LOS values are based on average delay and v/c ratio (degree of saturation) per movement. Intersection and Approach LOS values are based on average delay for all movements (v/c not used). Roundabout Capacity Model: SIDRA Standard. Delay Model: SIDRA Standard (Geometric Delay is included). Gap-Acceptance Capacity: SIDRA Standard (Akçelik M3D). HV (%) values are calculated for All Movement Classes of All Heavy Vehicle Model Designation. DocuSign Envelope ID: AB259DAD-E1F4-4927-9B6D-D48F19435899 USER REPORT FOR NETWORK SITE All Movement Classes Project: 44th_Five Roundabout_Build_Option 2_2025 - REVISED August 2022 HTi Template: Movement Report for Appendix Site: 1 [NE 44th St and NE 43rd St-PM (Site Folder: General)] Network: 2 [Renton-to-Bellevue: Year 2025 NE 44th Street PM (Network Folder: General)] New Site Site Category: (None) Roundabout Vehicle Movement Performance DEMAND FLOWS ARRIVAL FLOWS 95% BACK OF QUEUE Mov ID Turn Deg. Satn Aver. Delay Level of Service Prop. Que Effective Stop Rate Aver. No. Cycles Aver. Speed [ Total HV ][ Total HV ][ Veh.Dist ] veh/h %veh/h %v/c sec veh ft mph South: 43rd Driveway 3 L2 3 3.0 3 3.0 0.075 9.4 LOS A 0.4 10.0 0.56 0.56 0.56 29.4 8 T1 1 3.0 1 3.0 0.075 3.8 LOS A 0.4 10.0 0.56 0.56 0.56 29.2 18 R2 68 3.0 68 3.0 0.075 4.3 LOS A 0.4 10.0 0.56 0.56 0.56 26.7 Approach 73 3.0 73 3.0 0.075 4.5 LOS A 0.4 10.0 0.56 0.56 0.56 27.0 East: 44th 1 L2 102 3.0 102 3.0 0.567 7.8 LOS A 5.2 134.0 0.41 0.39 0.41 28.7 6 T1 561 3.0 561 3.0 0.567 2.7 LOS A 5.2 134.0 0.41 0.39 0.41 28.4 16 R2 53 3.0 53 3.0 0.567 3.1 LOS A 5.2 134.0 0.41 0.39 0.41 27.4 Approach 716 3.0 716 3.0 0.567 3.4 LOS A 5.2 134.0 0.41 0.39 0.41 28.3 North: 43rd Driveway 7 L2 235 3.0 235 3.0 0.335 11.2 LOS B 2.1 54.2 0.74 0.83 0.74 23.8 4 T1 1 3.0 1 3.0 0.335 6.0 LOS A 2.1 54.2 0.74 0.83 0.74 27.0 14 R2 32 3.0 32 3.0 0.335 6.5 LOS A 2.1 54.2 0.74 0.83 0.74 26.4 Approach 267 3.0 267 3.0 0.335 10.6 LOS B 2.1 54.2 0.74 0.83 0.74 24.3 West: 44th 5 L2 74 3.0 74 3.0 0.304 9.1 LOS A 1.9 48.1 0.57 0.53 0.57 29.0 2 T1 229 3.0 229 3.0 0.304 3.5 LOS A 1.9 48.1 0.57 0.53 0.57 26.1 12 R2 5 3.0 5 3.0 0.304 4.4 LOS A 1.9 48.1 0.57 0.53 0.57 27.9 Approach 308 3.0 308 3.0 0.304 4.8 LOS A 1.9 48.1 0.57 0.53 0.57 27.2 All Vehicles 1364 3.0 1364 3.0 0.567 5.2 LOS A 5.2 134.0 0.52 0.52 0.52 27.2 Site Level of Service (LOS) Method: Delay & Degree of Saturation (SIDRA). Site LOS Method is specified in the Network Data dialog (Network tab). Roundabout LOS Method: Same as Signalised Intersections. Vehicle movement LOS values are based on average delay and v/c ratio (degree of saturation) per movement. Intersection and Approach LOS values are based on average delay for all movements (v/c not used). Roundabout Capacity Model: SIDRA Standard. Delay Model: SIDRA Standard (Geometric Delay is included). Gap-Acceptance Capacity: SIDRA Standard (Akçelik M3D). HV (%) values are calculated for All Movement Classes of All Heavy Vehicle Model Designation. DocuSign Envelope ID: AB259DAD-E1F4-4927-9B6D-D48F19435899 QUEUE DISTANCE (AVERAGE) Largest Average Back of Queue Distance for any lane on the approach (feet) Site: 1 [NE 44th St and NE 43rd St-AM (Site Folder: General)]Network: 1 [Renton-to-Bellevue: Year 2025 NE 44th Street AM (Network Folder: General)] New Site Site Category: (None) Roundabout SIDRA INTERSECTION 9.0 | Copyright © 2000-2020 Akcelik and Associates Pty Ltd | sidrasolutions.com Organisation: HEFFRON TRANSPORTATION, INC.| Licence: NETWORK / 1PC | Processed: Tuesday, August 9, 2022 11:38:32 AM Project: C:\Users\Zach Goulson\OneDrive -Heffron Transportation, Inc\Zach -HTI\Projects\Kennydale Gateway\Sidra\44th_Five Roundabout_Build_Option 2_2025 -REVISED August 2022 HTi.sip9 Colour code based on Queue Storage Ratio [ < 0.6 ][ 0.6 –0.7 ][ 0.7 –0.8 ][ 0.8 –0.9 ][ 0.9 –1.0 ][ > 1.0 ] Queue Model: HCM Queue Formula. Project site is here DocuSign Envelope ID: AB259DAD-E1F4-4927-9B6D-D48F19435899 QUEUE DISTANCE (PERCENTILE) Largest 95% Back of Queue Distance for any lane on the approach (feet) Site: 1 [NE 44th St and NE 43rd St-AM (Site Folder: General)]Network: 1 [Renton-to-Bellevue: Year 2025 NE 44th Street AM (Network Folder: General)] New Site Site Category: (None) Roundabout SIDRA INTERSECTION 9.0 | Copyright © 2000-2020 Akcelik and Associates Pty Ltd | sidrasolutions.com Organisation: HEFFRON TRANSPORTATION, INC.| Licence: NETWORK / 1PC | Processed: Tuesday, August 9, 2022 11:38:32 AM Project: C:\Users\Zach Goulson\OneDrive -Heffron Transportation, Inc\Zach -HTI\Projects\Kennydale Gateway\Sidra\44th_Five Roundabout_Build_Option 2_2025 -REVISED August 2022 HTi.sip9 Colour code based on Queue Storage Ratio [ < 0.6 ][ 0.6 –0.7 ][ 0.7 –0.8 ][ 0.8 –0.9 ][ 0.9 –1.0 ][ > 1.0 ] Queue Model: HCM Queue Formula. DocuSign Envelope ID: AB259DAD-E1F4-4927-9B6D-D48F19435899 QUEUE DISTANCE (AVERAGE) Largest Average Back of Queue Distance for any lane on the approach (feet) Site: 1 [NE 44th St and NE 43rd St-PM (Site Folder: General)]Network: 1 [Renton-to-Bellevue: Year 2025 NE 44th Street PM (Network Folder: General)] New Site Site Category: (None) Roundabout SIDRA INTERSECTION 9.0 | Copyright © 2000-2020 Akcelik and Associates Pty Ltd | sidrasolutions.com Organisation: HEFFRON TRANSPORTATION, INC.| Licence: NETWORK / 1PC | Processed: Tuesday, August 9, 2022 11:38:42 AM Project: C:\Users\Zach Goulson\OneDrive -Heffron Transportation, Inc\Zach -HTI\Projects\Kennydale Gateway\Sidra\44th_Five Roundabout_Build_Option 2_2025 -REVISED August 2022 HTi.sip9 Colour code based on Queue Storage Ratio [ < 0.6 ][ 0.6 –0.7 ][ 0.7 –0.8 ][ 0.8 –0.9 ][ 0.9 –1.0 ][ > 1.0 ] Queue Model: HCM Queue Formula. DocuSign Envelope ID: AB259DAD-E1F4-4927-9B6D-D48F19435899 QUEUE DISTANCE (PERCENTILE) Largest 95% Back of Queue Distance for any lane on the approach (feet) Site: 1 [NE 44th St and NE 43rd St-PM (Site Folder: General)]Network: 1 [Renton-to-Bellevue: Year 2025 NE 44th Street PM (Network Folder: General)] New Site Site Category: (None) Roundabout SIDRA INTERSECTION 9.0 | Copyright © 2000-2020 Akcelik and Associates Pty Ltd | sidrasolutions.com Organisation: HEFFRON TRANSPORTATION, INC.| Licence: NETWORK / 1PC | Processed: Tuesday, August 9, 2022 11:38:42 AM Project: C:\Users\Zach Goulson\OneDrive -Heffron Transportation, Inc\Zach -HTI\Projects\Kennydale Gateway\Sidra\44th_Five Roundabout_Build_Option 2_2025 -REVISED August 2022 HTi.sip9 Colour code based on Queue Storage Ratio [ < 0.6 ][ 0.6 –0.7 ][ 0.7 –0.8 ][ 0.8 –0.9 ][ 0.9 –1.0 ][ > 1.0 ] Queue Model: HCM Queue Formula. DocuSign Envelope ID: AB259DAD-E1F4-4927-9B6D-D48F19435899