Science News from research organizations Satellites are exposing weak bridges in America and around the world Satellites may soon help spot the world’s weakest bridges before they collapse. Date: March 8, 2026 Source: University of Houston Summary: Satellites are giving scientists a powerful new way to watch over the world’s bridges. Using radar imaging, researchers can detect millimeter-scale movements that may signal early structural problems long before inspectors notice them. The study found many bridges—especially in North America—are aging and increasingly vulnerable, but satellite monitoring could sharply reduce the number classified as high-risk. The approach could be especially valuable in regions where traditional monitoring barely exists. Share: Facebook Twitter Pinterest LinkedIN Email FULL STORY Scientists have discovered that satellites can detect tiny structural shifts in bridges worldwide, revealing early warning signs of potential failures. The technology could help monitor most long-span bridges on Earth—especially in regions where traditional inspections are rare. Scientists are using satellites to reveal which bridges around the world may be at risk of failure -- and how to catch problems before disaster strikes. Adding satellite monitoring to bridge inspections reduces the number of structures labeled high risk by about one third. Among the bridges that still rank as high risk, roughly half could benefit from ongoing observations from space. The biggest gains could occur in regions such as Africa and Oceania, where bridge monitoring is currently limited or almost nonexistent. A researcher from the University of Houston is helping identify vulnerable bridges across the planet and offering a new way to address potential failures before they become catastrophic. In a global analysis of 744 bridges published in Nature Communications , Pietro Milillo and collaborators from several international institutions evaluated the condition of bridges around the world. Their results showed that bridges in North America are generally in the poorest condition, followed by those in Africa. The team also proposed a strategy that could transform how infrastructure is monitored worldwide by using satellites to track bridge stability and detect warning signs early. Aging Infrastructure and a Growing Risk Many of the bridges identified in the study are approaching the limits of their intended lifespan. Construction of bridges in North America surged during the 1960s, meaning many of these structures are now decades old and nearing or surpassing their original design life. To address this challenge, researchers are turning to space based monitoring systems that rely on Synthetic Aperture Radar. This technology captures high resolution images frequently and covers large areas of the planet, while also providing access to extensive historical data. "Our research shows that spaceborne radar monitoring could provide regular oversight for more than 60 percent of the world's long-span bridges," said Milillo, co author of the study and an associate professor of civil and environmental engineering at UH. "By integrating satellite data into risk frameworks, we can significantly lower the number of bridges classified as high-risk, especially in regions where installing traditional sensors is too costly." Detecting Tiny Movements From Space The international research team included Dominika Malinowska from Delft University of Technology (TU Delft) and the University of Bath, Cormac Reale and Chris Blenkinsopp from the University of Bath, and Giorgia Giardina from TU Delft. They relied on a remote sensing method known as Multi-Temporal Interferometric Synthetic Aperture Radar (MT-InSAR). This technique can complement traditional inspections by identifying extremely small shifts in structures. The system can measure movements as small as a few millimeters caused by slow geological processes such as landslides or ground subsidence. It can also reveal unusual patterns across wide areas that might signal emerging structural issues. Bridges represent some of the most fragile components of transportation systems, yet the current approaches used to monitor them have clear limitations. Visual inspections carried out in person can be costly and sometimes subjective. They are also typically performed only twice a year, which means early warning signs of deterioration may go unnoticed between inspections. Structural Health Monitoring (SHM) sensors provide a more continuous way to track structural performance. However, these systems are usually installed only on newer bridges or structures already known to have issues. According to the study, fewer than 20% of the world's long span bridges are equipped with these sensors, leaving many structures without consistent monitoring. A Satellite Based Monitoring Solution "Remote sensing offers a complement to SHM sensors, can reduce maintenance costs, and can support