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HomeMy WebLinkAboutItem 4a. Prado Road Interchange Project - Architectural and Aesthetic Design Refinements ARCHITECTURAL REVIEW COMMISSION AGENDA REPORT SUBJECT: PRADO ROAD INTERCHANGE PROJECT – ARCHITECTURAL AND AESTHETIC DESIGN REFINEMENTS BY: Matt Horn, Project Manager Phone Number: 805-423-0200 Email: mhorn@slocity.org APPLICANT/ REPRESENTATIVE: City of San Luis Obispo RECOMMENDATION Review the proposed aesthetic direction for the Prado Road Interchange Project (Interchange Project) and provide advisory recommendations regarding the inclusion of the following additional design elements into the design theme: 1. Inclusion of the seven sisters on the fence and/or bridge rail 2. Inclusion of the tower elements The ARC’s guidance will be used to refine the aesthetic package through continued coordination with the Caltrans Landscape and Structures staff to support completion of the final design. 1.0 REPORT IN BRIEF The Prado Road Interchange Project will create a new connection across US 101 and serve as an important gateway along the future Prado Road corridor. As final design advances, the City is working with Caltrans to refine the architectural a nd landscape treatments so the project provides a cohesive and recognizable gateway while remaining cost-conscious, durable, maintainable, and compatible with applicable Caltrans requirements. On August 4, 2026, the City Council selected the Base Theme (Attachment A - “Base Option”) as the starting point for continued aesthetic development and requested Architectural Review Commission (ARC) input on two potential enhancements: the placement and extent of the Seven Sisters motif on the bridge railing and/or fall protection fencing, and the inclusion of architectural tower elements as gateway features. The ARC is being asked to evaluate these elements for their contribution to the overall gateway character, visual compatibility with the Base Theme, appropria te scale and placement, and anticipated cost. Preliminary estimates identify approximately $2 05,000 in potential aesthetic enhancements, including architectural barrier treatments, perforated fencing, and tower elements. These costs are in addition to appr oximately $4 million already included in the project estimate for architectural treatment of the mechanically stabilized earth walls. Meeting Date: 9/21/2026 Item Number: 4a Time Estimate: 60 min Page 11 of 32 Item 4a Architectural Review Commission Report – September 21, 2026 ARC recommendations will be used to refine the aesthetic package through continued coordination with the Caltrans District Landscape Architect, Caltrans Structures, and the project design team. Selected treatments will then be evaluated for engineering feasibility, safety, constructability, durability, maintenance, and cost before incorporation into the final project design. 2.0 PROJECT SUMMARY AND PRADO ROAD CORRIDOR Prado Road is planned as a continuous east-west transportation corridor extending from Madonna Road on the west to Broad Street on the east. The completed corridor will address a longstanding lack of east-west connectivity in the southern portion of the City and serve vehicles, transit, emergency, bicyclists, and pedestrian service needs. It will connect existing neighborhoods, commercial and public-service areas, US 101, San Luis Ranch, and planned development east of South Higuera Street. The corridor will be completed through three projects described below and shown in Figure 1 below: 2.1 Prado Road Interchange Project The Interchange Project will install a new interchange at US 101 that will include the following improvements: • New bridge over US 101 connecting Prado Road and Dalido Drive. • Reconstructed northbound on and off ramps and Prado Road. • Widen Prado Road • Realign Elks Lane. • Install Bicycle and pedestrian shared use facilities along Prado Road. Figure 1: Related Project Vicinity Map Page 12 of 32 Item 4a Architectural Review Commission Report – September 21, 2026 • Underground electrical and communication facilities. The project’s location and scale make its aesthetic design important both to travelers on US 101 and to users of Prado Road. 2.2 Prado Creek Bridge Replacement Project The Prado Creek Bridge Replacement Project (Bridge Project) is immediately east of the Interchange Project and will replace the existing bridge carrying Prado Road over San Luis Obispo Creek near South Higuera Street. The bridge was constructed in 1957 and classified by Caltrans as structurally deficient in 2001. The replacement will provide modern vehicle, bicycle, and pedestrian facilities and improve the Prado Road and South Higuera Street intersection and multimodal connections toward Sierra Meadows Drive. Although the Bridge and Interchange Projects have separate limits, funding sources, environmental documentation, and delivery requirements, they form adjoining portions of the same corridor. Their visible materials, colors, fencing, landscaping, wall treatments, and other recurring features should provide continuity without requiring identical designs. 2.3 Future Prado Road Extension The future Prado Road Extension will continue the corridor east from Sout h Higuera Street toward Broad Street and is expected to be implemented incrementally with future private development. 3.0 PROJECT BACKGROUND 3.1 Previous Project Development The Interchange Project has completed the Project Initiation Document and environmental approval phases, including City Council approval of the Project Report in 2024. Final design began in 2025 and is now advancing through preparation of plans, specifications, and estimates, right-of-way and utility coordination, geotechnical and hydraulic investigations, structural type-selection reports, and environmental revalidation. A completed value analysis reduced the elevated structure by approximately 1,300 feet and lowered construction costs while maintaining the project’s required safety, operational, and multimodal functions. The project team is currently refining the design in coordination with Caltrans, incorporating City Council direction on aesthetics and utility undergrounding, and completing the Supplemental Project Report needed to document design changes made since environmental approval. Geotechnical field investigations are currently underway to obtain the required information to develop the design details for support foundations, pavement, drainage, retaining walls, and other i mprovements. Following completion of final design, the project must secure remaining right -of-way interests, complete utility relocations and permitting, obtain Caltrans approvals, and assemble the construction funding package before advertising the project for bids. Construction is presently anticipated in the summer of 2029 and will likely be constructed concurrent with the Bridge Project to reduce disruption, improve sequencing, and avoid duplicated construction activities. Page 13 of 32 Item 4a Architectural Review Commission Report – September 21, 2026 4.0 CITY COUNCIL DIRECTION AND REQUEST TO ARC On August 4, 2026, the City Council reviewed the Interchange Project’s design development, value engineering recommendations, utility undergro unding needs, multimodal improvements, funding strategy, and proposed architectural character. Council supported advancing the project with cost-conscious design refinements, preserving space for a potential future bicycle and pedestrian connection along Elks Lane, initiating the utility undergrounding process, and pursuing competitive grants to reduce the City’s financial exposure. Council selected the Base Theme as the starting point for continued aesthetic development and requested that the ARC review two potential enhancements: incorporation of the Seven Sisters motif into the bridge railing and/or fall protection fencing, and inclusion of tower elements as gateway features. Council determined that the ARC was well positioned to provide focused design guidance on these elements while allowing the project team to maintain project momentum and continue advancing future design submittals without delay. Figure 2 below shows renderings of the Base Theme. These renderings can be seen in greater detail included as Attachment A. Figure 2: Renderings of the Prado Road Interchange utilizing the Base Theme Design. Page 14 of 32 Item 4a Architectural Review Commission Report – September 21, 2026 4.1 Fencing and Bridge Rail The current Base Theme includes the Seven Sisters motif on the bridge railing visible from the Prado Road overcrossing. The ARC is asked to recommend whether the motif should remain on the railing, be incorporated into the fall protection fencing, or appear on both as a coordinated treatment. The pedestrian and bicycle fall protection fencing provides a practical location for the motif because it can be integrated into the architectural metalwork and visible from both Prado Road and US 101 vantage points. The final design will also need to satisfy applicable fall protection, anti -climb, structural loading, sight distance, drainage, durability, corrosion resistance, graffiti removal, and component replacement requirements. Figure 3: Rendering showing the Seven Sisters design internal to the structure as well as in the safety railing. Page 15 of 32 Item 4a Architectural Review Commission Report – September 21, 2026 4.2 Tower Element The current Base Theme does not include prominent tower elements. Council requested that tower elements be evaluated as a potential gateway feature and requested that the ARC recommend whether tower elements should be incorporated into the project. Tower elements could provide a visual gateway marker, help establish a stronger architectural identity for the interchange, and potentially provide an additional safety benefit when integrated with the bridge fencing. The tower and fencing configuration could be designed to discourage climbing or unaut horized access around the ends of the protective fencing to areas where a person could fall or jump from the bridge. Council identified this potential safety benefit as an additional consideration in evaluating whether Figure 4: Renderings of the Conceptual Tower Element Page 16 of 32 Item 4a Architectural Review Commission Report – September 21, 2026 tower elements should be incorporated into the project. Any proposed tower treatment would need to be coordinated with the bridge fencing and satisfy applicable Caltrans safety, anti-climb, structural, operational, inspection, and maintenance requirements. 5.0 COST AND AESTHETIC VALUE The aesthetic concepts presented in this report remain preliminary, and detailed quantities and final specifications will continue to be refined through coordination with the Caltrans District Landscape Architect, Caltrans Structures, and the project design te am. As the design advances, aesthetic treatments will also be evaluated for constructability, durability, maintenance requirements, and cost. The current project cost estimate already includes approximately $4 million for architectural treatment of the mechanically stabilized earth (MSE) walls. This treatment is considered part of the Base Theme and is therefore not an additional cost associated with the aesthetic enhancements under consideration by the ARC. Based on the project engineer’s preliminary assessment, the following order-of- magnitude costs have been identified for potential aesthetic enhancements beyond the architectural wall treatments already included in the project estimate: Aesthetic Enhancement Preliminary Quantity Unit Preliminary Cost Architectural Treatment – Barrier (7 sisters motif on Bridge Barrier) 300 SF $30,000 Aluminum Perforated Fence (7 sisters motif on Safety Fencing) 300 LF $75,000 Architectural Towers 4 LS $100,000 Total Potential Enhancements $205,000 These costs are preliminary and are intended to provide the ARC with a general understanding of the relative cost of individual aesthetic enhancements. They should not be interpreted as final construction estimates. The approximately $205,000 in potential enhancements represents a relatively small incremental cost compared with the architectural treatments already incorporated into the project design and overall project cost. These cost estimates are intended to allow the ARC to consider individual aesthetic elements based on their contribution to the gateway character and to weigh the anticipated aesthetic value of each improvement against its estimated cost. Page 17 of 32 Item 4a Architectural Review Commission Report – September 21, 2026 6.0 NEXT STEPS 1. Document ARC recommendations, including the preferred location and treatment of the Seven Sisters motif and the preferred tower concept. 2. Refine the Base Theme and prepare coordinated fencing, barrier, tower, wall, lighting, and landscape concepts. 3. Coordinate the refined concept with the Caltrans District Landscape Architect and Caltrans Structures. 4. Confirm safety, structural, maintenance, inspection, and constructability requirements and prepare detailed cost estimates for selected treatments. 5. Incorporate accepted recommendations into the final design, Supplemental Project Report, and Caltrans submittal. 7.0 ATTACHMENTS A. Base Theme Renderings and Component Details Page 18 of 32 PRADO INTERCHANGE Preliminary Concepts San Luis Obispo, CA August 27, 2026 ARCHITECTURE Page 19 of 32 ARCHITECTURE PRADO INTERCHANGE / Preliminary Concepts San Luis Obispo, CA CONTENTS Base Option Pedestrian On Interchange - Day & Night On US HWY 101 - Day & Night Detail Add Ons Option Pedestrian On Interchange - Day & Night On US HWY 101 - Day & Night Detail Page 20 of 32 ARCHITECTURE PRADO INTERCHANGE / Preliminary Concepts San Luis Obispo, CA BASE OPTION Page 21 of 32 ARCHITECTURE PRADO INTERCHANGE / Preliminary Concepts San Luis Obispo, CA BASE OPTION /PEDESTRIAN ON INTERCHANGE - DAY Fencing - Wire Mesh Barrier - 9 Sisters Formliner Page 22 of 32 ARCHITECTURE PRADO INTERCHANGE / Preliminary Concepts San Luis Obispo, CA BASE OPTION /PEDESTRIAN ON INTERCHANGE - NIGHT Standard roadway & pedestrian lighting Page 23 of 32 ARCHITECTURE PRADO INTERCHANGE / Preliminary Concepts San Luis Obispo, CA BASE OPTION /ON US HWY 101 - DAY Abutment - Standard panels Island - Two tiered system with signage and local plantings Barrier - Textured for visual separation Page 24 of 32 ARCHITECTURE PRADO INTERCHANGE / Preliminary Concepts San Luis Obispo, CA BASE OPTION /ON US HWY 101 - NIGHT Island - Uplighting for signage Page 25 of 32 ARCHITECTURE PRADO INTERCHANGE / Preliminary Concepts San Luis Obispo, CA BASE OPTION /DETAIL Island - Defensive landscaping Barrier - Textured for visual separation Page 26 of 32 ARCHITECTURE PRADO INTERCHANGE / Preliminary Concepts San Luis Obispo, CA ADD ONS OPTION Page 27 of 32 ARCHITECTURE PRADO INTERCHANGE / Preliminary Concepts San Luis Obispo, CA ADD ONS OPTION /PEDESTRIAN ON INTERCHANGE - DAY Fencing - 9 Sisters perforated panels, large scale Towers - Match endcaps & creates gateway Page 28 of 32 ARCHITECTURE PRADO INTERCHANGE / Preliminary Concepts San Luis Obispo, CA ADD ONS OPTION /PEDESTRIAN ON INTERCHANGE - NIGHT Towers - Lighting emphasizes gateway Page 29 of 32 ARCHITECTURE PRADO INTERCHANGE / Preliminary Concepts San Luis Obispo, CA ADD ONS OPTION /ON US HWY 101 - DAY Abutment - Custom geometric panels Towers - Gateway markers & barrier Page 30 of 32 ARCHITECTURE PRADO INTERCHANGE / Preliminary Concepts San Luis Obispo, CA ADD ONS OPTION /ON US HWY 101 - NIGHT Island - Uplighting for signage and walls Tower - Lighting for placemaking Page 31 of 32 ARCHITECTURE PRADO INTERCHANGE / Preliminary Concepts San Luis Obispo, CA ADD ONS OPTION /DETAIL Fencing - 9 sisters, large scale Tower - Frence Transition Page 32 of 32