Carnegie Mellon University

Stock image of bridge

June 08, 2023

Social Equity of Bridge Management

Just over a year ago, the Fern Hollow bridge in Pittsburgh made news when it fell, plunging cars and a transit bus into the ravine below. The incident placed a national spotlight on bridge health and safety. Cari Gandy, a joint Ph.D. student in Civil & Environmental Engineering and Engineering & Public Policy, analyzed how bridge conditions differ between communities in the United States. 

“Of infrastructure types, we focused our research on highway bridges because bridges in poor condition can be dangerous to both the users and to the surrounding communities,” Gandy says. Her research with Professors Daniel Armanios and Costa Samaras, “Social Equity of Bridge Management" was recently published in the ASCE Journal of Management in Engineering. 

Gandy’s research combined National Bridge Inventory records with neighborhood demographic data from the U.S. Census, providing an assessment of the equity of bridge management in the United States. She found that historically Black or African American communities were associated with a greater likelihood of having bridges in worse condition—even when accounting for household income. 

This study built upon previous work that found that lower-income and historically marginalized communities in Pennsylvania were associated with fewer new bridge projects. Additionally, bridges that were built in those communities were associated with lower clearance heights that restricted bus and freight traffic. To understand the performance of bridges beyond the initial siting and design decisions, Gandy looked at the condition ratings assigned by bridge inspectors across the United States for the last 30 years.

“Our study connects infrastructure data and community characteristics to assess social equity on a national scale, and we provide a roadmap for broader equity assessments of infrastructure,” says Gandy.

Gandy mentions that her time at CEE helped her to dive into research regarding engineering equity. “CEE provides such a unique opportunity to explore the social implications of our built environment. My understanding of infrastructure management was shaped by the scholarly, practical, and policy-making experience of the faculty.”

Gandy acknowledges that in a perfect situation, evidence-based decisions are used to reveal historical trends and reduce bias in infrastructure investments. But that data is not always readily available. ”Local public works departments may not have the resources to analyze their infrastructure data in this way, let alone combine it with socioeconomic and demographic data like we have done.”

Her work adds to an effort in the federal government to take a more holistic approach to bridge health. Gandy provided input into the development of the US Department of Transportation’s recently launched Equitable Transportation Community Explorer. She believes that her research will support innovative solutions that come from engineers and residents local to a particular bridge. “Local people know their communities best. Therefore, local agencies need the resources, tools, and direction to sustain infrastructure effectively and equitably.”