Success Story: Nature-Based Solutions in Roadway Widening
Raleigh includes nature-based solutions in its roadway widening project
Project Purpose
Sandy Forks Road was a busy, two-lane road showing signs of aging. The road was considered one of the worst in Raleigh due to congestion, roadway disrepair and environmental degradation from people walking alongside the road and destroying vegetation. Climate hazards like flooding blocked travel along this important route during emergencies while runoff from the roadway surface affected water quality. The City of Raleigh began the Sandy Forks Road widening project to repair the aging roadway, increase the road’s capacity, incorporate sidewalks and bike lanes, reduce water pollution and improve the road’s resilience to flooding and other climate hazards.
Quick Facts
- The project widened the roadway from two lanes to four or six lanes in some areas, resulting in substantial tree removal.
- The Sandy Forks Road widening is the first (and only as of December 2023) road project in Raleigh that applied for Greenroads Certification. The City used the certification requirements as a way to gain knowledge and skills on applying nature-based solutions. The completed project was awarded silver certification.
Spotlight on Equity
The area in which this project was constructed was not home to any disadvantaged communities. Instead, this project served as a pilot project for the City of Raleigh in incorporating environmental sustainability into road design. The inclusion of vegetated areas and bioretention cells helps protect residents from flooding. This vegetation, along with newly planted trees, improves water quality and helps cool the area. The City is now considering these types of solutions for other projects in areas with high percentages of disadvantaged residents.
What are bioretention cells?
Bioretention cells are depressions in the landscape that capture stormwater and filter it through engineered layers of soil and vegetation, including native plants, to naturally filter out pollutants. (The City of Raleigh, 2023)
| Key Info | |
|---|---|
| Location | Raleigh, N.C. |
| Estimated Costs | $9.9 million |
| Published | March 1, 2024 |
| Project Contacts |
|---|
| Tiffanie Mazanek Communications Analyst City of Raleigh Tiffanie.Mazanek@raleighnc.gov (919) 215-5141 |
| Sylvester Percival Roadway Design and Construction Manager City of Raleigh, Engineering Services Department Sylvester.Percival@raleighnc.gov (919) 996-4053 |
| Related Resources |
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- The City of Raleigh held public meetings to discuss the repair of Sandy Forks Road in 2012 and 2013.
- In 2014, the City held project design meetings. The City selected a 3.4-mile stretch of road between Six Forks Road and Falls of Neuse Road to implement the project.
- The City awarded a project contract in 2015. The initial construction phase finished in fall 2016. The project included a vegetated median that spanned a maximum width of 16.5 feet.
- Final touches on the project wrapped up in 2017, including the installation of public art and educational signage related to water treatment and environmental resilience.
- In 2018, Sandy Forks Road was awarded a Silver Greenroads Certification. A certification signifies that the project successfully incorporated road sustainability features.
- The total cost of this project was approximately $9.9 million.
- The City of Raleigh used Capital Improvement Plan funds and other city-initiated funding.
City of Raleigh
- Sandy Forks Road became a divided two-lane road with a median and extra turning lanes in some places.
- The roadway was repaired to aid traffic flow and increase its lifespan. Road lifespan is generally about 40 years; however, the City of Raleigh added extra pavement that should add an extra 10 years.
- The City included nature-based stormwater solutions in the project. The median vegetation and three bioretention cells support flood prevention and water quality improvement. In addition, the City used a more eco-friendly asphalt mixture to minimize the road’s impacts on water quality.
- The project included removing invasive species and planting native species, which has helped support a more natural ecosystem. Educational signage about the sustainable initiatives of the Sandy Forks Road project is helping to keep residents informed.
- Sandy Forks Road was chosen in part for its ability to test the value of bioretention cells. The City placed one of these cells along the road’s median. Bioretention cells require infrastructure underneath the roadway. The bioretention cells along Sandy Forks Road are used as evidence of their value. Raleigh now has many roads with bioretention cells running along the roadside.
- Other improvements in the project included the construction of new sidewalks and bike lanes and the use of energy-saving light fixtures.
- Recycling and reusing materials were important aspects of the project. The City recycled trees removed for the project into lumber and stumps into wood chips. The City also crushed asphalt from the previous roadway and used it in the new surface.
- This project featured one of Raleigh's first public art installations as part of a road project. The City now includes art in most of its development initiatives.
- The project earned the highest score globally awarded at the time to achieve its Greenroads Certification. A silver certification was still the highest award given by the global transportation nonprofit, Sustainable Transport Council, as of December 2023.
City Communications Analyst Tiffanie Mazanek noted that this project would have been an excellent opportunity to consider grant options. “For more and more of our projects, we are finding federal and state funding that can offset some of the costs. There are a lot more opportunities for grant funding when we include sustainably or environmental actions.”
She also mentioned that the extra paperwork that goes into the Greenroads Certification can be a hassle for small communities. But overall, it helped the City of Raleigh think about alternatives and find environmentally friendly solutions that they have begun implementing in other road projects. Mazanek also remarked that bike transportation was a large talking point during the project design phase. The community has been vocal in asking for bike lanes that are separated from the roadway with delineators. While communities love the new lanes, they would prefer a clear separation between lanes and vehicles to make them even safer.
Mazanek also remarked that bike transportation was a large talking point during the project design phase. The community has been vocal in asking for bike lanes that are separated from the roadway with delineators. While communities love the new lanes, they would prefer a clear separation between lanes and vehicles to make them even safer.
The City of Raleigh. (2023, November 3). Roadway Bioretention Areas. Retrieved from https://raleighnc.gov/stormwater/services/green-stormwater-infrastructure/roadway-bioretention-areas