More connected street networks are more resilient

By Megan Link

As we have seen recently with the bridge and interstate collapses in Baltimore and Pennsylvania, disruptions to our street network severely impact travel. Natural disasters, like earthquakes and floods and targeted disasters, terrorist attacks, disrupt travel patterns, raising questions about why some cities are more vulnerable to these disasters than others. Especially in urban areas, when a central street is removed from the equation, people and goods still need to move to and from destinations. A new study looks at urban areas worldwide to determine what street network characteristics make them more resilient and vulnerable before and after disasters. Areas with disconnected street design like North America and Oceania are among the most vulnerable. 

 Disruptions tend to be less impactful in urban areas with more connections, or redundancy, and fewer chokepoints. Researchers from the University of Southern California analyzed over 8,000 urban areas in 178 countries to conduct a global study on network design and vulnerability. They determined the effects of various disruptions to the street network by modeling conditions before and after a disruption. Street networks with high centrality, or proximity to other streets and intersections, largely determine the network’s ability to recover from both natural and targeted disasters. Areas with more nodes are less vulnerable overall. 

According to their findings, North America and Oceania are the most vulnerable regions, possibly because they have more disjointed, disconnected networks with more chokepoints. Disasters also affect these regions the most.  In areas like the United States, where many areas emphasize the suburban model of dead-ends and long, circuitous routes, this is especially harmful during disasters like floods, earthquakes, and terrorist attacks. 

To further analyze the effects of post-disaster recovery on network design, the authors compared specific urban areas within North America. When comparing Salt Lake City, Utah, with Wichita, Kansas, it became evident that Wichita’s tightly connected grid of small blocks facilitated easier travel during disruptions. In contrast, Salt Lake City’s longer, winding routes experienced significantly longer travel times during similar disruptions. “Wichita has a higher average node degree and a lower chokepoint score than Salt Lake City, illustrating how connectedness shapes street network vulnerability.” 

Source: Boeing, et. al (2024). Wichita and Salt Lake City disruption differences, based on street network characteristics.

As climate change continues to lead to more environmental disasters, planning for a resilient future starts with a connected street network.  

Photo Credit: Kaique Rocha via Pexels, unmodified. License