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HomeMy WebLinkAboutSGM MEMORANDUM DATE: December 30, 2025 TO: John Leybourne, Glenn Hartman, Garfield County Planning FROM: Dan Cokley, PE, PTOE SUBJECT: Harvest Roaring Fork PUD – Transportation Studies Review This memo provides an initial review of the Harvest project regarding the following submittals associated with the Updated Planned Unit Development Application dated July 29, 2025. • Traffic Impact Study (TIS) prepared by Kimley-Horn and Associates dated April 18, 2025. • Preliminary Multimodal Analysis (MMA) prepared by Kimley-Horn and Associates dated November 18, 2025. • CDOT State Highway Access Permits 325027, 325028 dated April 18, 2025. To summarize the overall review, the proposed SH 82 improvements represented in the TIS are consistent with the approved State Highway Access Permits and provide reasonable mitigation to the traffic impacts to the regional roadway network. The TIS and Access Permits have been coordinated with CDOT to date. It is recommended that the Applicant address the following requests for additional information. • Trip Generation o 90% Internal Capture Rate is atypical with the application and development plans lacking detail to verify that assumption. Provide additional details to support that internal capture rate for retail land use or use industry standard rate. • Trip Directional Distribution o Provide a justified basis for an assumed directional split of 70% / 30% upvalley as existing traffic counts and recent TIS’s in the area have used similar splits in the downvalley direction. • Spring Valley Road intersection o Provide additional analysis of CR 114 / SH 82 intersection for the 2035 Background + project using the existing intersection configuration and signal timing, including an updated directional distribution. • Accessory Dwelling Units o A reasonable estimate of the number of potential ADU’s should be included in the project trip generation calculation. • Project Accesses to include assessment of the following. o Ingress / egress lane configuration to address volumes and queuing o Entering sight distance requirements • Multimodal Analysis o Given the magnitude of the development, the Applicant should work with RFTA to identify a location within the development or along SH 82 for a transit stop near the village center to maintain a ½ mile radius for potential users that will adequately serve the development. • Garfield County LUC 4-203 L requires addressing the County Road Impact Fees and assessment of construction traffic impacts to the County and State Road system. Any changes in proposed land uses identified on the Access Permits should require an update to the April 2025 traffic impact study. Detailed Review Summary The proposed land uses are assumed to be those represented in the TIS and Access Permits (shown below). Outside of those documents, the development land use is represented as 1500 residential units and 55,000 sf of commercial space as designated in the PUD application and shown below. Regarding the SH 82 proposed Reduced Conflict Intersections (RCI, RCUT, Median U-Turn…) for this corridor segment, these intersections will provide safer access to the state highway for the project intersections and Cattle Creek Road users. Reduced left-turn conflict intersections are geometric designs that alter how left-turn movements occur. These intersections simplify decision-making for drivers and minimize the potential for higher severity crash types, such as head-on and angle. These intersections will be signalized. The Level of Service (LOS) of the proposed RCUT intersections is generally acceptable except for intersection #5 in 2055 operating at LOS E. LOS D-F is common for many side street approaches to SH 82 during peak hours throughout the valley. The LOS information is summarized in the table below copied from the TIS. Cattle Creek operates at LOS A. Specific detailed comments are provided below, most of which have been discussed with CDOT Region 3 traffic staff who have been involved in the coordination and review of the TIS and Access Permit process. • Trip Generation o Internal Capture – An internal capture rate of 90% is applied using an assumption that the “Access to the retail portion is indirect and out of the way for a typical street-front retail location attracting area wide traffic”. The application and development plans lack detail to verify that assumption. o Multi-modal trip reduction – Not applied in the trip generation calculations but discussed in the multimodal analysis letter. o Trip Generation uses “peak hour of generator” rather than “peak hour of adjacent street” period which results in higher peak hour volumes than typical traffic impact analysis methodology. o Considering all the above factors, the trip generation assumptions used in the TIS provide for a reasonable analysis of the impact of the proposed development. • Trip Directional Distribution o Assumed to be split 70% / 30% in the upvalley direction. This is in comparison to recent TIS’s completed in the vicinity for Flying M, Spring Valley, and Lake Springs Ranch which assumed similar splits in the downvalley direction. o Existing traffic counts at Spring Valley Road and Cattle Creek do not appear to support the proposed directional distribution. o A justifiable basis should be provided for this assumption. • Spring Valley Road intersection o Existing intersection level of service and safety has been a long-standing issue requiring a two-part solution.  Improvements of SH 82 auxiliary lanes to meet design speed and storage capacity requirements. CDOT has initiated an improvement plan to extend the southbound (upvalley) left turn lane.  Improvements to side street approach lanes to facilitate removal of the current split phase signal cycle that will improve level of service. It is my understanding the County is responsible for these side-street improvements.  The proposed development may further degrade the Delay / LOS modeled at the intersection but does not directly access the intersection and may not be responsible for mitigation. The TIS does not provide a direct comparison of the effect of the project traffic to the intersection. • Accessory Dwelling Units o It is my understanding that there is a potential for 450 ADU’s associated with the proposed single-family homes that are not included in the TIS. o These units have the potential to increase the peak hour traffic at the access locations by 15% to 25%. o SGM has reviewed and performed studies where ADU’s have been included in the Trip Generation assumptions. o A reasonable estimate of the number of potential ADU’s should be included in the project trip generation calculation. • Multimodal Analysis o To provide a more accurate comparison of the current ridership at RFTA Bus Stop 312 currently serving Willitts Town Center and the Tree Farm to the potential ridership of the Harvest Roaring Fork development, each development’s land use mix should be used rather than overall “area” of the developments. o Generally, multi-modal options are attractive when situated within ¼ to ½ mile of origin / destination of the user. Although it’s known that the Roaring Fork Valley exhibits better than average regional multimodal usage, the existing transit stop at the Spring Valley intersection is over ½ mile to the nearest point of the development and greater than one mile to the “village center”. o Given the magnitude of the development, the Applicant should work with RFTA to identify a location within the development or along SH 82 for a transit stop that will adequately serve the development near the village center to maintain a ½ mile radius for potential users. Please let me know if the County has any questions or additional information to review regarding this matter.