Susana Road Reconstruction Project (Finalist)

Location

Susana Road, Unincorporated Community of Rancho Dominguez

City or County Responsible for Project

County of Los Angeles

Category

Roads: Efficient and Sustainable Road Maintenance, Construction and Reconstruction Projects.

Author

Leslie Schenk

Organization

Los Angeles County Department of Public Works

Address

900 South Fremont Avenue, Alhambra, CA 91803

Phone

(626) 458-5946

Project Description

The County of Los Angeles Department of Public Works has utilized sustainable pavement treatments with great success since 2008. We continue our commitment to preserving and improving the quality of our roads in a cost effective and environmentally responsible way. The statewide mandate (AB32) to reduce greenhouse gas (GHG) emissions with limited budgets were key motivators for developing our sustainable approach that included (1) focusing on preserving roads in good condition first; (2) using recycled materials in pavement treatments; and (3) reutilizing materials in place when reconstructing our roads. The Susana Road Project showcases the benefits when properly applying this sustainable approach. Susana Road is located within an industrial part of the unincorporated community of Rancho Dominguez. The 2-mile long major arterial generates significant heavy truck traffic. The pavement condition was rated as poor and exhibited extensive distresses and localized base failure. It was inadequate for the current traffic loading and required reconstruction. The traditional reconstruction method of removing and replacing the existing road materials was estimated to cost $4.6 million. The County’s proposed sustainable reconstruction method of reutilizing the in-place materials was estimated to save $3.2 million and achieved significant environmental benefits. The Project scope included removing the top 3” of the existing asphalt concrete (AC) for use in the Cold Central Plant Recycling (CCPR) process; cement stabilizing the remaining AC, base, and subgrade; placing the removed 3” of Reclaimed Asphalt Pavement (RAP) using the CCPR process on the cement stabilized base material; and constructing 2” of Polymer Modified AC (containing 15% RAP) on the CCPR AC. This method required less construction workdays, mitigating traffic impacts. Environmental benefits included a 49% reduction in GHG emissions, 56% reduction in energy consumption, and 28,000 cubic yards of landfill reduction. The cost savings of $3.2 million was reinvested to improve other County roads. In addition, new bike lanes were included in the Project along with vegetated bioswales and tree well basins to facilitate storm water infiltration. These innovative features create permeable surfaces which replenish groundwater and improve water quality. They also reduce the volume of water that enters the storm drain system. Managing the County’s road network with limited funding and reducing GHG in our pavement treatments are strategic issues for Public Works. Our three-pronged approach is a straightforward formula for addressing these issues in a practical manner. By employing these sustainable practices, the County is achieving reductions in GHG and energy used as well as realizing significant cost savings. Our experiences with these sustainable treatments have direct benefits to our constituents. We welcome opportunities to share our experiences and collaborate with other local agencies.