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HomeMy WebLinkAboutC_Applicant_Response_ to_Transpo_Analysis.pdf 117402.5 1191 Second Avenue, Suite 1800 Seattle, WA 98101-2996 206-623-9372 vnf.com June 7, 2021 Matt Herrera, AICP – Interim Current Planning Manager City of Renton Community & Economic Development 1055 S. Grady Way Renton, WA 98057-3232 MHerrera@Rentonwa.gov Re: Transpo Group - Cedar River Apartments Independent Transportation and Mitigation Analysis Dear Matt, On behalf of the applicant for the Cedar River Apartments Project, SRMRenton, LLC, I am writing in response to the Transpo Group memorandum dated May 7, 2021 (“Transpo Memo”) concerning their Cedar River Apartments Independent Transportation and Mitigation Analysis. Together with transportation engineers at William Popp Associates (“WPA”), we have had opportunity to review the Transpo Memo and data files used to support the Transpo Memo. We offer the following comments in response: 1. The Transpo model may have overestimated traffic queuing and delays. Based on WPA’s review of Transpo data files, certain aspects of the Transpo model may exacerbate delays and queuing observed in the Transpo Memo. First, WPA identified a difference in the “signal cycle offset” used at SR 169/I-405 NB Ramps (Intersection 4 in the Transpo Memo) between the WPA model and the Transpo model. Signal cycle offsets facilitate the platooning of traffic; i.e., in order for the downstream signal to be green when vehicles arrive, the start of the appropriate green phase must be coordinated with the upstream green phase for all intersections in that coordinated direction. The signal cycle offsets establish the precise time required for the coordinated green phase to begin at a given intersection. The offset in the WPA model was computer optimized at 12 seconds, whereas the Transpo model utilized a 7-second offset. It is not clear why the Transpo model utilized a different signal cycle offset at Intersection 4, but the difference results in substantially longer queuing lengths on westbound SR-169 during the AM peak hour. Second, WPA observed that conversion of the HOV lane to a general-purpose lane at the southbound I-405 on-ramp suggests further adjustment to the Transpo model. WPA’s existing Matt Herrera, AICP – Interim Current Planning Manager - 2 - June 7, 2021 117402.2 conditions model, relied on by Transpo, included a “hard-coded” adjustment to southbound lane usage at Sunset Blvd/NE 3rd St (Intersection 1 in the Transpo Memo) premised on HOV lane exclusivity at the I-405 on-ramp. This hard-coded adjustment in the WPA model carries over in the Transpo model, even though Transpo’s analysis assumes the HOV lane no longer exists. If the Transpo model allowed Synchro to balance the volume of traffic in the southbound lane approaches, rather than carry forward the hard-coded adjustment for the continued existence of the HOV lane, the Transpo model results should favorably impact operations at Intersection 1 and westbound SR-169. These modeling discrepancies may overestimate traffic delays and queuing both with and without the Project. Thus, for purposes of the City’s threshold SEPA determination, the City should view the Transpo Memo as a worst-case scenario with respect to traffic impacts in 2024. 2. SEPA Review should not incorporate use of an “Intersection Approach” for evaluating level of service and delays. The Transpo Memo evaluates level of service (“LOS”) and delays in 2024 at the operational intersection levels, both with and without the Project.1 Results shown in Table 1 of the Transpo Memo indicate that the only drop below LOS D occurs during the weekday PM peak hour at Intersection 1. Bronson Way/Houser Way (Intersection 2) is already forecast to operate at LOS F during the weekday PM peak hour without the Project, but delays actually lessen at that same intersection in the with-Project scenario. However, the Transpo Memo proceeds with an intersection approach-based analysis to identify additional with-Project drops in LOS and increased delays in Table 2. The Transpo Memo acknowledges that, “while one or more approaches may be impacted, it can still result in minimal impact to the overall intersection delay.” Transpo concludes that the majority of intersections studied will operate at LOS D or better. See Transpo Memo at 10. City of Renton Transportation Policy T-48.C., in relevant part, states as follows: Through the SEPA review process, apply the following operational LOS standard at intersections that could be impacted by a proposed development: 1. Arterials and Collectors: Except as listed in C.2, apply a standard of LOS D. Renton’s Comprehensive Plan does not call for narrow evaluation of LOS at each intersection approach for purposes of SEPA review, but rather, calls for an operational LOS standard at the overall intersection level. While the results shown in Table 2 of the Transpo Memo 1 We understand Transpo analyzed the Project as reaching build-out in 2024. Due to delays in the entitlement process, the Project is unlikely to reach full build-out by 2024. Nevertheless, SRMRenton does not object to Transpo’s use of full Project build-out in 2024 for purposes of producing a conservative, or worst-case-scenario, analysis that could occur prior to completion of the WSDOT Express Toll Lane Project. Matt Herrera, AICP – Interim Current Planning Manager - 3 - June 7, 2021 117402.2 purport to “better emphasize the changes between the scenarios,” they should not be used for purposes of identifying significant impacts for purposes of SEPA review. 3. An Adaptive Traffic Control System, as proposed by Transpo, would effectively mitigate potential impacts identified in the Transpo Memo. Notwithstanding our concerns regarding adjustments to the Transpo model and the narrow scope of analysis included in the Transpo Memo, SRMRenton agrees that the mitigation identified by Transpo – namely an Adaptive Traffic Control System, such as the Split Cycle Offset Optimization Technique (“SCOOT”) system – would effectively mitigate the “worst case scenario” of traffic delays and queuing identified in the Transpo Memo. As indicated in the Transpo Memo, the SCOOT system has improved travel time reliability and reduced vehicle queuing by as much as 38 percent in other areas. Installation of the SCOOT system would mitigate the LOS E result at Intersection 1 and reduce delays experienced along the SR 169 corridor both with and without the Project. WPA’s observations regarding the signal cycle offset used at Intersection 4 in the WPA model versus the Transpo model serves as further evidence that the SCOOT system will benefit the Project area. WPA’s preliminary analysis shows that the 7-second signal cycle offset used in the Transpo model produces queuing lengths that are over 1000 feet longer, both without the Project and with the Project, when compared to the 12-second signal cycle offset used in the WPA model. This directly supports that optimization of signal timing using the SCOOT system would significantly improve traffic queuing and delays in the SR 169 corridor. 4. Dual turn lanes from Cedar River Park Drive should be recognized as an additional mitigation measure. The Transpo Memo identifies noticeable impacts at the intersection of SR 169 and Cedar River Park Drive, specifically at the northbound approach in the AM peak hour. See Transpo Memo at 10-11. As shown in Figure 5, traffic entering onto westbound SR 169 would experience delays largely due to queuing in the far-right lane leading to the I-405 northbound on-ramp. This is consistent with WPA’s observations in their Traffic Impact Analysis (“TIA”) dated July 6, 2020. See TIA at 55-56 (“maximum queues may extend into the Project entrance road at full occupancy”). However, WPA further recommended that the approach configuration at Cedar River Park Drive should be restriped to provide dual left turn lanes with a shared right turn lane (curb lane). According to WPA, approximately 40% of traffic exiting the Project and turning left at the SR 169/Cedar River Park Dr intersection during the AM peak hour is anticipated to be headed to the I-405 southbound on-ramp or westbound on Bronson Way. Thus, a dual left turn lane would better distribute northbound traffic on Cedar River Park Drive into the left and middle lane of SR 169. The Transpo Memo did not include a second left turn lane at Cedar River Park Drive in their analysis. Inclusion of this additional mitigation measure would relieve the potential impacts identified at the intersection of SR 169 and Cedar River Park Drive, and accordingly, should be considered an additional measure that would mitigate impacts of the Project. Matt Herrera, AICP – Interim Current Planning Manager - 4 - June 7, 2021 117402.2 5. WSDOT ETL Improvements and Traffic Impact Fees to be paid by the Applicant will provide direct and substantial relief to existing and future traffic queuing and delays experienced on SR 169 and at the I-405 interchanges. As previously observed in the TIA, the mainline widening for the WSDOT Express Toll Lane (“ETL”) project that is slated for completion in late 2024 should result in substantially decreased congestion and queuing for the SR 169 corridor intersections and roadways analyzed in connection with the Project. Furthermore, SRMRenton will be responsible for payment of traffic impact fees potentially exceeding $4,000,000 on construction of the Project.2 Taking into consideration WSDOT’s programmed ETL improvements and the mitigation measures identified in the Transpo memorandum (SCOOT system) and the TIA prepared by WPA (dual turn lanes from Cedar River Park Drive), and the Transpo Memo likely indicating a “worst case scenario” of traffic impacts, the City should conclude that traffic impacts resulting from a full build-out of the Project will not rise above the level of significance. Thank you for the opportunity to provide these comments. We look forward to a prompt SEPA determination from the Environmental Review Committee concerning SRMRenton’s project. Very truly yours, H. Ray Liaw HRL:dph cc: Jim Rivard, SRM Development Jimmy Blais, Gary Merlino Construction Co. Andy Loos, SRM Development 2 Based on application of the 2020-21 fee schedule, the residential component of the project would result in impact fees $3,230,925 for 481 residential units ($6,717.10/unit), approximately $128,966 for the retail component ($26.58/sf), and $823,500 in fees for the medical office building ($32.94/sf).