South Grand Boulevard Great Streets Initiative
Landscape Performance Benefits
- Projected to reduce vehicle emissions by 50% as a result of reducing delays by reconfiguring the street and improving signal timing.
- Projected to reduce the peak ground-level temperature by 7.8°F in areas where asphalt was replaced with high-albedo pervious concrete. Large planted areas and tree canopy help to further cool the streetscape.
- Expected to reduce average traffic speed by 17 mph, which is projected to result in a 85% drop in accidents, saving $3 million in estimated costs and damages. This also reduces the probability of pedestrian fatality upon vehicular impact from 40% to 5%.
- Projected to reduce the noise level from an average of 68dB to below 60dB by reducing traffic speeds. This falls within the range that allows a comfortable conversation, improving the environment for pedestrians and outdoor dining.
- Expected to increase satisfaction with the street aesthetics. 81% of survey respondents felt that the proposed design would have a good or very good appearance. Only 22% said this about the former streetscape.
- Increased annual sales tax revenue by 14% in the first year after redevelopment. The project was initially projected to increase revenue by 19% over a 10-year period.
At a Glance
Design Workshop, Inc.
Former Land Use
South Grand Boulevard and Arsenal Street
St. Louis, Missouri 63118
South Grand Boulevard is a culturally diverse historic district, known for its architectural heritage and its multitude of international restaurants. Selected as one of four Great Streets Initiative pilot projects in 2009, the South Grand redevelopment transformed a six-block corridor into a vibrant destination, improving the pedestrian experience, enhancing safety, and providing opportunities for continued economic development. The streetscape enhancement project featured extensive community involvement, including a keypad and online polling service in which residents voted on nine different potential streetscape options. The designers analyzed these options using 40 metrics that addressed environmental, social, economic, and aesthetic considerations. The final boulevard design enhances walkability, incorporates innovative stormwater management, and creates a memorable public realm which builds on the character of the community.
- In order to reduce traffic speeds and improve pedestrian and driver safety, the road width was reduced and bulb-outs were added at intersections, shortening crosswalk distances from 56 to 37 ft.
- Tactile crosswalk striping, accessible ramps, visual and audio cues, and detectable warnings and signalization improve ADA accessibility. The corridor now meets federal requirements for accessibility at all intersections, which was of special concern because of the project’s close proximity to the Missouri Schools for the Deaf and Blind. The corridor is now used by these students to familiarize themselves with urban environments.
- Nearly all of the materials removed from the site during construction were reused, reducing landfill waste. Concrete, bricks and asphalt were used as sub-base and trenching fill. Existing subsoils, site furnishings, granite curbing, and bricks were also reused on-site.
- Prior to the redevelopment, outdoor dining interfered with pedestrian needs due to the limited width of the sidewalk. Sidewalk widths were increased from 6.5 to 15 feet, adding around 1,000 square feet of outdoor dining space that accommodates 337 seats. This creates a lively gathering place that encourages people to spend more time in the area. The expanded sidewalk also makes room for significantly larger tree boxes.
- The percentage of pervious surfaces increased from 2% to 50% along the street. The project was one of the first in St. Louis to use porous paving materials.
- This corridor was one of the first in St. Louis to feature rain gardens. In Phase 2 of the project, rain gardens will be placed at all intersection bulb-outs, along with tree boxes containing native perennials and forbs that will filter and infiltrate stormwater.
- The soil volume for each tree was increased from 100 to 1,000 cubic feet, which will enhance tree growth, health, and longevity.
- All planting materials are native to Missouri and locally available. Designed with seasonal interest, the new vegetation can withstand the harsh street conditions and is expected to increase the populations of birds and butterflies.
The design team was hired with only four months to gain community approval and produce the construction documents in order to avoid losing funding for the project. Moreover, with a multicultural population, it was important to produce a public realm that would accommodate diverse needs, including those of business owners, commuters, pedestrians and residents.
In order to streamline the approval process, the designers led a compressed community engagement process, which included online surveys, keypad polling, and special interest meetings. The designers also offered alternatives for those who could not attend meetings or engage with the project online, such as a dedicated hotline and voice messaging service. During the consultation, the designers developed nine options for the community to review and consider, which the design team then evaluated using 40 metrics. By addressing issues such as stormwater, noise, air quality, urban heat island effect, vehicular speed, crime rates, employment opportunities, and public art, these metrics educated the public on the existing site conditions and on the goals and trade-offs of the design alternatives. The community ultimately selected a preferred alternative from three short-listed options. The landscape architect recommended a pilot test of the concept, which determeined that the redesign would lower traffic speeds, drop noise levels and achieve other objectives. The project then moved ahead with broad support from the community.
- With nine street alternatives, it was essential to evaluate the proposed designs based on the objectives identified by the users. A system of 40 metrics enabled the designers to show the opportunities and trade-offs associated with different design solutions, including pedestrian realm, economic development, and visual appearance. These metrics were a critical citizen engagement tool and helped inform the compressed public engagement schedule.
- Some city officials opposed many elements of the proposed design, including rain gardens, smart parking meters, smart street lighting and porous pavement. Education and engagement assisted with this skepticism. The project could have achieved better traction earlier on had these officials received background training on sustainable design best practices.
- The design team was not contracted to oversee project construction, and thus several aspects of the design were changed without their consultation. It is imperative for the design team to be engaged during construction for successful implementation of original design intent.
Land Planner/Landscape: Design Workshop, Inc.
Transportation Planning: Nelson\Nygaard, TND Engineering
Civil Engineering: Horner and Shifrin, Inc.
Market Analysis: RCLCO
Art Planning: Via Partnership, LLP
Public Engagement: Hudson and Associates, LLC
Stormwater: University of Georgia School of Environmental Design
Street Trees: Jim Urban
Cost Estimating: Kwame Building Group
Site Surveying: Kowelman Engineering, Inc.
Irrigation and Planting Design: Austin Tao and Associates
Role of the Landscape Architect
The landscape architect focused on understanding the context of the project and developed a systematic approach for comprehensive community involvement in a short timeframe. The landscape architect designed the streetscape enhancement and produced construction documents, collaborating with an extensive team of market analysts, transportation planners, civil engineers, and art planners.
Case Study Prepared By
Research Fellow: Bo Yang, PhD, Assistant Professor, Utah State University
Research Assistant: Yue Zhang, MLA candidate, Utah State University
Research Assistant: Pamela Blackmore, BLA candidate, Utah State University
Firm Liaisons: Allyson Mendenhall, Kurt Culbertson, Sarah Endsley, Design Workshop