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Home My WebLink AboutSouthport West - Revised Traffic Scoping Memo TENW Transportation Engineering NorthWest Transportation Planning | Design | Traffic Impact & Operations 11400 SE 8th Street, Suite 200, Bellevue, WA 98004 | Office (425) 889-6747 MEMORANDUM DATE:February 8, 2022 TO:Michael Sippo City of Renton FROM:Jeff Schramm / Spenser Haynie TENW SUBJECT:Revised Traffic Impact Analysis Scoping for the proposed Southport West Mixed-Use (City of Renton) TENW Project #2021-263 This revised memorandum documents the preliminary traffic information for the Southport West mixed-use project located on the north side of Southport Drive N adjacent to the existing Southport development for the purpose of establishing a scope of work for the traffic impact analysis (TIA). This memo includes a project description and project trip generation estimate, as well as revised trip distribution and list of study intersections, and is an update to the previous memo (dated January 26, 2022) based on discussions with the City staff at the January 27, 2021 initial traffic scoping meeting. Project Description The current Southport West mixed-use project proposal includes the development of approximately 1,405,000 square feet (SF) of office space and 40,600 SF of retail space. The existing site has minimal traffic generation. Vehicular access to/from the proposed development would be provided by the existing Lake Washington Blvd/Southport Access and future Southport Drive/Park Avenue Extension signalized intersections. The vicinity map below shows the location of the existing Southport and the proposed Southport West sites. Southport West (Renton)Revised Traffic Scoping Memo TENW February 8, 2022 Page 2 Trip Generation The trip generation estimates for the proposed uses were based on methodology documented in the Institute of Transportation Engineers (ITE) Trip Generation Manual, 11th Edition (2021) for Land Use Codes (LUC) 710 (General Office Building) and 821 (Shopping Plaza). Adjustments to the total trip generation estimate were made to account for internal trips and pass-by trips, both of which are described next. Internal Trips are made by people making multiple stops within a development without generating new trips onto the adjacent street system. The internal trip adjustments were based on the methodology established in the ITE Trip Generation Handbook, 3rd Edition (2017). Note that internal trips were estimated including the portion of the existing Southport development that has been built to date and the anticipated occupancy of the existing Southport office space. This is appropriate given the potential for “capture” of trips between the residents and office employees at Southport, and the future additional office employees and residents and retail patrons at Southport West. This methodology is consistent with ITE Trip Generation practices given the opportunities for internal trip capture for residents, office employees and retail patrons within both Southport and Southport West. It should also be noted that there could be additional opportunities for internal trip capture between the Southport and Southport West uses and the existing Coulon Park and abundance of other residential and retail uses in the adjacent Landing project located within a short walking distance. However, in order to provide a more conservative evaluation of potential traffic impacts, the internal trip capture with The Landing and Coulon Park has not specifically been included, but should be acknowledged in the context of estimating future traffic generation and potential traffic impact fees and mitigation. Pass-by Trips are trips that are made by vehicles that are already on the adjacent streets and make intermediate stops at the commercial uses on route to a primary destination (i.e. on the way from work to home). The pass-by trips estimated in the trip generation calculations were based on studies included in the appendices of the ITE Trip Generation Manual, 11th Edition (2021). The resulting net new weekday AM and PM peak hour trip generation estimates for the proposed project are summarized in Table 1 and reflect the adjustments for internal trip capture and pass-by trips. Detailed trip generation calculations are included in Attachment A. Table 1 Southport West Trip Generation Summary Net New Trips Generated Time Period In Out Total Weekday AM Peak Hour 1,351 104 1,455 Weekday PM Peak Hour 181 1,167 1,348 Note: reflects net trips after accounting for internal trip captures from adjacent uses, and pass-by trips for retail. See Attachment A for details. Trip Distribution The distribution of trips (vehicles and trucks) generated by the proposed Southport West project was estimated based on existing travel patterns in the vicinity of the site as follows: Southport West (Renton)Revised Traffic Scoping Memo TENW February 8, 2022 Page 3 15 percent to/from the north on Lake Washington Blvd N 20 percent to/from the north on I-405 10 percent to/from the east on NE Sunset Blvd 30 percent to/from the south on I-405 10 percent to/from the south on Park Avenue N 15 percent to/from the west/south on Logan Avenue N The anticipated trip distribution patterns are also shown graphically in Attachment B. Note that this trip distribution is similar to the distribution patterns evaluated in the prior Southport EIS except that there is slightly more local traffic area roadways. Next Steps for TIA Upon your review of this revised information, please confirm the following for the traffic analysis: Confirm trip generation calculations, including pass-by and internal trip capture Confirm trip distribution approach Confirm study intersections for LOS evaluation: 1. Park Avenue N/Southport Drive N 2. Lake Washington Blvd N/Garden Avenue N/Southport Drive N 3. Lake Washington Blvd N/Coulon Park Drive 4. I-405 SB Ramps/N Southport Drive 5. I-405 NB Ramps/N Southport Drive 6. Lake Washington Blvd N/N 30th Street 7. Burnett Avenue N/N 30th Street 8. I-405 SB Ramps/N 30th Street 9. I-405 NB Ramps/N 30th Street 10.I-405 SB Ramps/NE 44th Street 11.I-405 NB Ramps/NE 44th Street Note that the intersections listed above are consistent with the intersections studied in the Southport EIS (1999). Confirm if both weekday AM and PM peak periods will require LOS analyses at study intersections Provide traffic studies from approved pipeline development projects in the area Confirm background growth rates to be used in analysis Provide most recent City 6-year TIP project list If you have any questions, please feel free to contact Jeff at (206) 396-8286 or schramm@tenw.com. Attachments: A. Detailed Trip Generation Calculations B. Revised Project Trip Distribution cc: Michael Christ – SECO Development Derek Janke – SECO Development Bhavik Rao – Urbancraft Consulting Southport West (Renton)Revised Traffic Scoping Memo Attachment A Trip Generation Calculations Land Use Size / Units ITE LUC 1 Trip Rate 1 Enter Exit Enter Exit Total AM PEAK HOUR Southport West Office 1,405,000 SF 710 Ln(T) = 0.86 Ln(X) + 1.16 88%12%1,430 195 1,625 Internal2 -47 -19 -66 1,383 176 1,559 Retail 40,600 SF 821 1.73 62%38%43 27 70 Internal2 -16 -10 -26 Pass-By3 40%-11 -7 -18 16 10 26 Southport Built to Date Multifamily Housing (Mid-Rise) 383 DU 221 T = 0.44(X) - 11.61 23%77%36 121 157 Internal2 -1 -4 -5 35 117 152 Office 712,752 SF 710 Ln(T) = 0.86 Ln(X) + 1.16 88%12%797 109 906 Internal2 -26 -10 -36 771 99 870 Retail 30,000 SF 822 2.36 60%40%43 28 71 Internal2 -16 -10 -26 Pass-By3 40%-11 -7 -18 16 11 27 Restaurant 10,000 SF 931 0.73 80%20%6 1 7 Internal2 -5 0 -5 Pass-By3 44%-1 0 -1 0 1 1 Hotel 347 rooms 310 T = 0.50(X) - 7.45 56%44%93 73 166 Internal2 0 -58 -58 93 15 108 Southport West Gross AM Peak Hour Trips Generated =1,473 222 1,695 Less Internal Trips (including Southport Built to Date) =-111 -111 -222 Less Pass-by Trips =-11 -7 -18 Southport West Total Proposed Net AM Peak Hour Trips = 1,351 104 1,455 Notes: 1. Land Use Code, trip rates, and directional splits from Institute of Transportation Engineers (ITE) Trip Generation Manual, 11th Edition, 2021. 2. Internal trip reductions based on methodology documented in the ITE Trip Generation Handbook, 3rd Edition, 2017. 3. Pass-By trips determined based on methodology included in the Appendices from Institute of Transportation Engineers (ITE) Trip Generation Manual, 11th Edition, 2021. Southport West Weekday Trip Generation Estimate Directional Split 1 Vehicle Trip Generation 1/26/2022 Land Use Size / Units ITE LUC 1 Trip Rate 1 Enter Exit Enter Exit Total PM PEAK HOUR Southport West Office 1,405,000 SF 710 Ln(T) = 0.83 Ln(X) + 1.29 17%83%253 1,236 1,489 Internal2 -4 -13 -17 249 1,223 1,472 Retail 40,600 SF 821 5.19 49%51%103 108 211 Internal2 -27 -40 -67 Pass-By3 40%-28 -30 -58 48 38 86 Southport Built to Date Multifamily Housing (Mid-Rise) 383 DU 221 T = 0.39(X) + 0.34 61%39%92 58 150 Internal2 -51 -30 -81 41 28 69 Office 712,752 SF 710 Ln(T) = 0.83 Ln(X) + 1.29 17%83%144 704 848 Internal2 -3 -7 -10 141 697 838 Retail 30,000 SF 822 Ln(T) = 0.71 Ln(X) + 2.72 50%50%85 85 170 Internal2 -22 -31 -53 Pass-By3 40%-24 -23 -47 39 31 70 Restaurant 10,000 SF 931 7.80 67%33%52 26 78 Internal2 -26 -19 -45 Pass-By3 44%-10 -5 -15 16 2 18 Hotel 347 rooms 310 T = 0.74(X) - 27.89 51%49%117 112 229 Internal2 -14 -7 -21 103 105 208 Southport West Gross PM Peak Hour Trips Generated =356 1,344 1,700 Less Internal Trips (including Southport Built to Date) =-147 -147 -294 Less Pass-by Trips =-28 -30 -58 Southport West Total Proposed Net PM Peak Hour Trips = 181 1,167 1,348 Notes: 1. Land Use Code, trip rates, and directional splits from Institute of Transportation Engineers (ITE) Trip Generation Manual, 11th Edition, 2021. 2. Internal trip reductions based on methodology documented in the ITE Trip Generation Handbook, 3rd Edition, 2017. 3. Pass-By trips determined based on methodology included in the Appendices from Institute of Transportation Engineers (ITE) Trip Generation Manual, 11th Edition, 2021. Southport West Weekday Trip Generation Estimate Directional Split 1 Vehicle Trip Generation 1/26/2022 Project Name:Organization: Project Location:Performed By: Scenario Description:Date: Analysis Year:Checked By: Analysis Period:Date: ITE LUCs1 Quantity Units Total Entering Exiting Office 2,531 2,227 304 Retail 141 86 55 Restaurant 7 6 1 Cinema/Entertainment 0 Residential 157 36 121 Hotel 166 93 73 All Other Land Uses2 0 Total 3002 2448 554 Veh. Occ. % Transit % Non-Motorized Veh. Occ. % Transit % Non-Motorized Office Retail Restaurant Cinema/Entertainment Residential Hotel All Other Land Uses2 Office Retail Restaurant Residential Hotel Office Retail Restaurant Cinema/Entertainment Residential Hotel Office Retail Restaurant Residential Hotel Office 28 1 0 0 Retail 16 3 1 0 Restaurant 0 0 0 0 Cinema/Entertainment 0 0 0 0 0 Residential 2 1 1 0 Hotel 55 3 0 0 Total Entering Exiting Land Use Entering Trips Exiting Trips All Person-Trips 3,002 2,448 554 Office 3% 10% Internal Capture Percentage 7% 5% 20% Retail 37% 36% Restaurant 83% 0% External Vehicle-Trips3 2,780 2,337 443 Cinema/Entertainment N/A N/A External Transit-Trips4 0 0 0 Residential 3% 3% External Non-Motorized Trips4 0 0 0 Hotel 0% 79% 4Person-Trips *Indicates computation that has been rounded to the nearest whole number. Estimation Tool Developed by the Texas Transportation Institute 1Land Use Codes (LUCs) from Trip Generation Informational Report, published by the Institute of Transportation Engineers. 2Total estimate for all other land uses at mixed-use development site-not subject to internal trip capture computations in this estimator 3Vehicle-trips computed using the mode split and vehicle occupancy values provided in Table 2-A 0 0 0 Table 5-A: Computations Summary Table 6-A: Internal Trip Capture Percentages by Land Use 0 Table 4-A: Internal Person-Trip Origin-Destination Matrix* Origin (From)Destination (To) Cinema/Entertainment 0 Origin (From)Destination (To) Cinema/Entertainment AM Street Peak Hour Table 1-A: Base Vehicle-Trip Generation Estimates (Single-Use Site Estimate) Land Use Development Data (For Information Only )Estimated Vehicle-Trips Table 2-A: Mode Split and Vehicle Occupancy Estimates Land Use Entering Trips Exiting Trips Table 3-A: Average Land Use Interchange Distances (Feet Walking Distance) NCHRP 8-51 Internal Trip Capture Estimation Tool Southport West TENW SJH 1/26/2022 Project Name: Analysis Period: Veh. Occ. Vehicle-Trips Person-Trips* Veh. Occ. Vehicle-Trips Person-Trips* Office 1.00 2227 2227 1.00 304 304 Retail 1.00 86 86 1.00 55 55 Restaurant 1.00 6 6 1.00 1 1 Cinema/Entertainment 1.00 0 0 1.00 0 0 Residential 1.00 36 36 1.00 121 121 Hotel 1.00 93 93 1.00 73 73 Office Retail Restaurant Residential Hotel Office 85 192 3 0 Retail 16 7 8 0 Restaurant 0 0 0 0 Cinema/Entertainment 0 0 0 0 0 Residential 2 1 24 0 Hotel 55 10 7 0 Office Retail Restaurant Residential Hotel Office 28 1 0 0 Retail 89 3 1 0 Restaurant 312 7 2 4 Cinema/Entertainment 0 0 0 0 0 Residential 67 15 1 0 Hotel 67 3 0 0 Internal External Total Vehicles1 Transit2 Non-Motorized2 Office 73 2154 2227 2154 0 0 Retail 32 54 86 54 0 0 Restaurant 5 1 6 1 0 0 Cinema/Entertainment 0 0 0 0 0 0 Residential 1 35 36 35 0 0 Hotel 0 93 93 93 0 0 All Other Land Uses3 0 0 0 0 0 0 Internal External Total Vehicles1 Transit2 Non-Motorized2 Office 29 275 304 275 0 0 Retail 20 35 55 35 0 0 Restaurant 0 1 1 1 0 0 Cinema/Entertainment 0 0 0 0 0 0 Residential 4 117 121 117 0 0 Hotel 58 15 73 15 0 0 All Other Land Uses3 0 0 0 0 0 0 1Vehicle-trips computed using the mode split and vehicle occupancy values provided in Table 2-A 2Person-Trips 3Total estimate for all other land uses at mixed-use development site-not subject to internal trip capture computations in this estimator *Indicates computation that has been rounded to the nearest whole number. Table 9-A (D): Internal and External Trips Summary (Entering Trips) Destination Land Use Person-Trip Estimates External Trips by Mode* Table 9-A (O): Internal and External Trips Summary (Exiting Trips) Origin Land Use Person-Trip Estimates External Trips by Mode* 0 0 0 Table 8-A (D): Internal Person-Trip Origin-Destination Matrix (Computed at Destination) Origin (From)Destination (To) Cinema/Entertainment 0 0 0 0 0 Table 7-A: Conversion of Vehicle-Trip Ends to Person-Trip Ends Land Use Table 7-A (D): Entering Trips Table 7-A (O): Exiting Trips Table 8-A (O): Internal Person-Trip Origin-Destination Matrix (Computed at Origin) Origin (From)Destination (To) Cinema/Entertainment 0 0 Southport West AM Street Peak Hour 1/26/2022 Project Name:Organization: Project Location:Performed By: Scenario Description:Date: Analysis Year:Checked By: Analysis Period:Date: ITE LUCs1 Quantity Units Total Entering Exiting Office 2337 397 1,940 Retail 381 188 193 Restaurant 78 52 26 Cinema/Entertainment 0 Residential 150 92 58 Hotel 229 117 112 All Other Land Uses2 0 Total 3175 846 2329 Veh. Occ. % Transit % Non-Motorized Veh. Occ. % Transit % Non-Motorized Office Retail Restaurant Cinema/Entertainment Residential Hotel All Other Land Uses2 Office Retail Restaurant Residential Hotel Office Retail Restaurant Cinema/Entertainment Residential Hotel Office Retail Restaurant Residential Hotel Office 15 1 4 0 Retail 4 15 42 10 Restaurant 1 11 5 2 Cinema/Entertainment 0 0 0 0 0 Residential 2 19 7 2 Hotel 0 4 3 0 Total Entering Exiting Land Use Entering Trips Exiting Trips All Person-Trips 3,175 846 2,329 Office 2% 1% Internal Capture Percentage 9% 17% 6% Retail 26% 37% Restaurant 50% 73% External Vehicle-Trips3 2,881 699 2,182 Cinema/Entertainment N/A N/A External Transit-Trips4 0 0 0 Residential 55% 52% External Non-Motorized Trips4 0 0 0 Hotel 12% 6% 4Person-Trips *Indicates computation that has been rounded to the nearest whole number. Estimation Tool Developed by the Texas Transportation Institute 1Land Use Codes (LUCs) from Trip Generation Informational Report, published by the Institute of Transportation Engineers. 2Total estimate for all other land uses at mixed-use development site-not subject to internal trip capture computations in this estimator 3Vehicle-trips computed using the mode split and vehicle occupancy values provided in Table 2-P 0 0 0 Table 5-P: Computations Summary Table 6-P: Internal Trip Capture Percentages by Land Use 0 Table 4-P: Internal Person-Trip Origin-Destination Matrix* Origin (From)Destination (To) Cinema/Entertainment 0 Origin (From)Destination (To) Cinema/Entertainment PM Street Peak Hour Table 1-P: Base Vehicle-Trip Generation Estimates (Single-Use Site Estimate) Land Use Development Data (For Information Only )Estimated Vehicle-Trips Table 2-P: Mode Split and Vehicle Occupancy Estimates Land Use Entering Trips Exiting Trips Table 3-P: Average Land Use Interchange Distances (Feet Walking Distance) NCHRP 8-51 Internal Trip Capture Estimation Tool Southport West TENW SJH 1/26/2022 Project Name: Analysis Period: Veh. Occ. Vehicle-Trips Person-Trips* Veh. Occ. Vehicle-Trips Person-Trips* Office 1.00 397 397 1.00 1940 1940 Retail 1.00 188 188 1.00 193 193 Restaurant 1.00 52 52 1.00 26 26 Cinema/Entertainment 1.00 0 0 1.00 0 0 Residential 1.00 92 92 1.00 58 58 Hotel 1.00 117 117 1.00 112 112 Office Retail Restaurant Residential Hotel Office 388 78 39 0 Retail 4 56 50 10 Restaurant 1 11 5 2 Cinema/Entertainment 0 0 0 0 0 Residential 2 24 12 2 Hotel 0 18 76 2 Office Retail Restaurant Residential Hotel Office 15 1 4 0 Retail 123 15 42 20 Restaurant 119 94 15 83 Cinema/Entertainment 24 8 2 4 1 Residential 226 19 7 14 Hotel 0 4 3 0 Internal External Total Vehicles1 Transit2 Non-Motorized2 Office 7 390 397 390 0 0 Retail 49 139 188 139 0 0 Restaurant 26 26 52 26 0 0 Cinema/Entertainment 0 0 0 0 0 0 Residential 51 41 92 41 0 0 Hotel 14 103 117 103 0 0 All Other Land Uses3 0 0 0 0 0 0 Internal External Total Vehicles1 Transit2 Non-Motorized2 Office 20 1920 1940 1920 0 0 Retail 71 122 193 122 0 0 Restaurant 19 7 26 7 0 0 Cinema/Entertainment 0 0 0 0 0 0 Residential 30 28 58 28 0 0 Hotel 7 105 112 105 0 0 All Other Land Uses3 0 0 0 0 0 0 *Indicates computation that has been rounded to the nearest whole number. Origin Land Use Person-Trip Estimates External Trips by Mode* 1Vehicle-trips computed using the mode split and vehicle occupancy values provided in Table 2-P 2Person-Trips 3Total estimate for all other land uses at mixed-use development site-not subject to internal trip capture computations in this estimator Table 9-P (O): Internal and External Trips Summary (Exiting Trips) 0 0 0 0 0 Table 9-P (D): Internal and External Trips Summary (Entering Trips) Destination Land Use Person-Trip Estimates External Trips by Mode* Origin (From)Destination (To) Cinema/Entertainment Origin (From)Destination (To) Cinema/Entertainment 0 8 2 0 0 Table 8-P (D): Internal Person-Trip Origin-Destination Matrix (Computed at Destination) Table 7-P: Conversion of Vehicle-Trip Ends to Person-Trip Ends Land Use Table 7-P (D): Entering Trips Table 7-P (O): Exiting Trips Table 8-P (O): Internal Person-Trip Origin-Destination Matrix (Computed at Origin) Southport West PM Street Peak Hour 1/26/2022 Southport West (Renton)Revised Traffic Scoping Memo Attachment C Trip Distribution