Public Works Department
DATE: January 30, 2024
TO: Council Transportation Committee
FROM: Aruna Bodduna, Transportation Planner
Dawn S. Cameron, Public Works Director
SUBJECT: Interim Castro Pedestrian Mall--Central Walkway Street Treatment Concepts
PURPOSE
Provide a recommendation to the City Council on the proposed central walkway street treatment concepts for the Interim Castro Pedestrian Mall.
BACKGROUND
In August 2022, a Council ad hoc subcommittee was created to review and provide direction on new design standards and guidelines, along with an implementation plan for the Interim Castro Street Pedestrian Mall. On March 20, 2023, the Interim Castro Pedestrian Mall Ad Hoc Subcommittee directed staff to identify placemaking opportunities through the incorporation of decorative design treatments in public areas, such as the social eddies 1 and central walkway.
While public art will be included in the permanent Pedestrian Mall project, the interim pedestrian mall will include some decorative pavement treatments that would be temporary in nature. The Ad Hoc Subcommittee also directed staff to receive feedback from the Visual Arts Committee (VAC) on decorative pavement designs for the central walkway.
GUIDELINES FOR CENTRAL WALKWAY TREATMENT CONCEPTS
The 16’ wide central walkway will extend along Castro Street from California Street to W est Evelyn Avenue, with the pavement treatment demarcating the central through zone and breezeway access (Figure 1). Gehl, in collaboration with City staff, developed the following six guidelines for the proposed street treatments: Scale, Visual Impact, Implementation Ease, Medium, Durability and Maintenance, and Cost.
1 Social eddies are social seating, hang-out areas, and play spaces that are publicly accessible and free to use.
Castro Interim Pedestrian Mall – Central Walkway Street Treatment Concepts January 30, 2024
Figure 1: Castro Street Zones and Treatment Area
1. Scale: The scale and complexity of the decorative treatment have a direct impact on the implementation timeline, cost, and maintenance that follows. Full surface coverage requires more upkeep as wear and tear are more visible. More complex detailing takes longer to implement and, therefore, takes longer to reapply. Within a three- to five-year time span, reapplication will be needed.
Recommended Approach: Use a partial treatment with coverage of about 50% of the treatment area where asphalt still shows between the application.
2. Visual Impact: The selected treatment should:
• V isually connect Castro Street across the 100 to 300 blocks through a unified design pattern or color;
• R epresent the character of Mountain View through color, imagery, or wayfinding to the wider City; and
• R einforce the functional and program plans by designating the spatial separation between the through zone and programming zone.
Castro Interim Pedestrian Mall – Central Walkway Street Treatment Concepts January 30, 2024
The visual impact will be dictated by the scale, colors, and details of the treatment.
Accordingly, treatments with high visual impact will come with higher implementation complexity and life-cycle costs.
Recommended Approach: Select a concept that has a high visual impact, but is less complex to implement (such as having fewer colors and simple geometric shapes).
3. Implementation Ease: The ease of implementation will depend on the material chosen and the scale and complexity of the treatment. Some material types will require multiple applications or contractor installation. The time and labor required for installation will increase wit h surface coverage and level of detail of the treatment design. The implementation ease or complexity will also affect businesses operating outdoor patios, and these businesses may find they will have to shut down outdoor patio operations during application and maintenance.
Recommended Approach: Avoid a treatment design that requires an overlay of multiple colors and patterns as this will add implementation and maintenance complexity.
4. Material/Medium: The material/medium chosen will impact each of the other criteria and ultimately have the greatest impact on the treatment. A few materials for consideration, along with a comparative cost of installation, include:
• Acrylic Asphalt Paint (Comparative Cost --$): This material does not require a multi - step appl ication; however, it wears faster and will require more frequent reapplication and/or touch-ups, possibly every one to two years. Power washing will contribute to wearing down the treatment.
• Streetbond Water Based Pavement Coating (Comparative Cost --$$): This material lasts longer, requires multi-step application and a longer implementation time frame, can be power washed, and requires less maintenance, potentially lasting up to 10 years before reapplication is needed.
• Epoxy Gravel (Comparative Cost--$$$): This material also lasts longer, requires multi- step application and a longer implementation time frame, can be power washed, and requires less maintenance, potentially lasting over 10 years before reapplication is needed.
• Preformed Thermoplastic (Comparative Cost --$$$$): This material last s the longest and is the most expensive option. This material has the lowest level of maintenance over time but requires specialized contractor installation and a lead time for custom design development.
Castro Interim Pedestrian Mall – Central Walkway Street Treatment Concepts January 30, 2024
The longevity of the material/medium depends on various factors such as treatment surface, site weather conditions, space usage, and wear and tear with ongoing maintenance activities. The timelines listed above are estimates provided by the material suppliers for a typical roadway application.
Recommended Approach: Use Acrylic Asphalt Paint that is easy to implement and maintain and could provide a short term opportunity to modify the design when reapplication is needed. Consider transitioning to Streetbond Water Based Pavement Coating after a couple of years if no design modifications are desired.
5. Durability and Maintenance: The durability and maintenance of the street treatment will be dictated by the medium chosen for the application. There is an inverse relationship between the upfront cost of the treatment material and the costs for maintenanc e across the life cycle of the project. There is some maintenance effort needed irrespective of the chosen material/medium.
6. Cost: The ultimate cost of the street treatment will be dictated by each of the other criteria, especially material/medium an d scale. A cost estimate will be developed after a design concept is selected.
ANALYSIS OF CENTRAL WALKWAY STREET TREATMENT CONCEPTS
Gehl developed the following central walkway street treatment concepts based on the criteria presented above. The treatments show part of a block, with decorative treatments to be repeated throughout or with variation across the three blocks. All concepts use a subset of the color palette from the City’s Brand Guidelines.
2 2 https://www.mountainview.gov/whats-happening/city-newsroom/logo-guidelines
Castro Interim Pedestrian Mall – Central Walkway Street Treatment Concepts January 30, 2024
Concept 1: Ribbons
- Colors: Four, three primary and one accent color
- Coverage: Approximately 55%
Castro Interim Pedestrian Mall – Central Walkway Street Treatment Concepts January 30, 2024
Concept 2A: Interlace
- Colors: Three rotating colors (possibility for more colors in odd-numbered intervals) - Coverage: Approximately 70%
Castro Interim Pedestrian Mall – Central Walkway Street Treatment Concepts January 30, 2024
Concept 2B: Interlace--Small
- Colors: Three rotating colors (possibility for more colors in odd-numbered intervals) - Coverage: Approximately 70%
Castro Interim Pedestrian Mall – Central Walkway Street Treatment Concepts January 30, 2024
Concept 3: Hopscotch Helix
- Colors: Four, three primary and one accent color
- Coverage: Approximately 25%
Castro Interim Pedestrian Mall – Central Walkway Street Treatment Concepts January 30, 2024
VISUAL ARTS COMMITTEE FEEDBACK
The decorative central walkway street treatments concepts discussed above were presented to the VAC on January 17, 2024. The general feedback from the VAC was supportive of adding street treatments to the central walkway and for the color scheme used for the concepts. In addition to the recommendation on the preferred concept and color scheme, the VAC discussed the material/medium of the treatment and preferred a material that could withstand power washing and other regular maintenance efforts. In summary, the VAC passed the following motions:
1. Approve the ribbon concept with more coverage (up to 70%) by expanding the ribbon widths. (6-1 vote)
2. Appro ve the design with the colors as proposed. (7-0 vote)
3. Recommend that the City use the Streetbond Water -Based Pavement Coating instead of the Acrylic Asphalt Paint so that the treatment can be power washed. (6-1 vote)
The ribbon concept as presented provided approximately 55% coverage. Staff can explore expanding or widening the ribbon widths for more coverage; however, staff recommends the coverage be balanced with ensuring the ribbons provide the sense of movement and flow envisioned.
Staff recommends starting with Acrylic Asphalt Paint for ease of implementation, including less impact on the business operations, and to provide an opportunity to have the design in place for a time before committing to a more expensive and longer term medium.
NEXT STEPS
Based on the Council Transportation Committee’s feedback, staff will d evelop cost estimate for the preferred concept and present it to the City Council for approval.
QUESTIONS FOR THE COUNCIL TRANSPORTATION COMMITTEE
1. Which central walkway street treatment concept does the Committee recommen d, and does the Committee have any feedback about the preferred concept?
2. Does the Committee have any feedback on the colors or medium recommended?
AB-DSC/LL/4/PWK
979-01-30-24M-1
Attachment: 1. Street Treatment Concepts