The site of the prefectural road collapse in Yashio, Saitama Prefecture. Left: January 28, 2025, the day the sinkhole occurred; right: January 25, 2026.
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Japan is approaching what Nihon University civil engineering professor Ichiro Iwaki calls a "watershed moment"—and not in a good way.
Iwaki, a vocal advocate for infrastructure reform, warns that the country is now at a critical juncture in the management of its aging public works. If action is not taken urgently, the question will no longer be whether accidents happen, but how often.
Built in a Generation, Crumbling in Another
Japan's infrastructure story is rooted in speed. Unlike other advanced economies that developed their public works networks over centuries, Japan compressed that process into roughly two decades. The highways, bridges, and tunnels that define modern Japan were largely built during the high-growth period of the 1960s and 70s.
"That was around 50 years ago," Iwaki notes. "Not all infrastructure deteriorates at the 50-year mark, but structures exposed to harsh conditions begin showing signs of trouble around that time."
Those signs are already visible. The 2012 collapse of ceiling panels inside the Sasago Tunnel on the Chuo Expressway killed nine people and briefly seized national attention—before the issue faded from public view.
In recent years, similar incidents have followed. In January 2025, a busy intersection in Yashio, Saitama collapsed without warning, swallowing a delivery truck whole after a sewer pipe installed in 1983 ruptured due to decades of internal corrosion.
Each generates headlines. Each is eventually forgotten.
Iwaki fears the pattern is about to change. Not because awareness will finally take hold, but because the incidents will simply become too frequent to ignore.
Three Interlocking Failures
When asked what is driving Japan's infrastructure management crisis, Iwaki resists single-cause explanations. The problem, he says, is structural across three dimensions: technology, institutional systems, and public ownership.
On the technology front, the issue is not just a shortage of engineers—though that is acute—but also the slow adoption of methods and tools suited to a maintenance-era reality. Many local governments still operate under frameworks designed for construction, not upkeep.
The institutional dimension is equally stubborn. "The systems in place today are largely the same systems used when the infrastructure was being built," Iwaki explains. "They were not designed for what we face now."
But it is the third failure—public awareness—that Iwaki returns to most forcefully. Without citizens treating this as a personal concern rather than an abstract government problem, political will cannot be sustained, and budgets cannot be secured.
"Ultimately, politics responds to public sentiment," he says. "If people don't see this as their problem, the funding and the policy won't follow."
Triage, Not Total Maintenance
One of the more uncomfortable truths Iwaki raises is that Japan cannot maintain everything it has built. Resources—both human and financial—are simply insufficient. The question is no longer whether to prioritize, but how.
For major national infrastructure—expressways, Shinkansen structures—he advocates a shift to preventive maintenance, catching problems before they become emergencies. But for the thousands of local bridges and rural roads that stitch together communities across the country, the calculus is different.
"If there are five routes connecting two points, and that destination is a small, depopulated settlement, maintaining all five is neither necessary nor possible," he says. "Consolidate to three, or two, or even one—but make sure that one is reliably maintained."
This is not, he emphasizes, an argument for abandoning rural communities. The language of "compact cities"—relocating people when infrastructure becomes unviable—draws his skepticism. The goal should be scaled-back but durable connectivity, not population displacement.
Digital Tools, Human Limits
Technology offers partial relief. Iwaki is an advocate for what he calls "simple DX"—accessible digital tools that allow municipalities to conduct inspections and diagnostics without specialist personnel or significant expense. Sensors, data platforms, and AI-assisted monitoring can extend the reach of a depleted workforce.
The caveat is usability. High-end systems that local governments cannot operate or afford offer nothing. The tools that matter are those that can be adopted immediately, without deep technical expertise, by the kinds of small municipal teams—often five engineers or fewer—that are the reality across rural Japan.
Cautious, Qualified Hope
Asked whether he is optimistic, Iwaki's answer is carefully hedged. The current government, he says, has at least placed resilience and disaster preparedness at the center of its agenda—a meaningful signal, if not a guarantee.
But awareness at the top does not automatically reach the periphery. Asked whether the national focus on resilience translates to rural Japan, he acknowledges the gap while pushing back on the idea that the regions are being written off. "The weight is shifting," he says. "More people are now working on exactly these local problems. It's not where it needs to be, but it's moving."
What Iwaki is clear about is the timeline. Japan is at the watershed. The decisions made in the next few years—on budgets, on technology adoption, on institutional reform, and on whether citizens choose to engage—will determine whether the country manages a controlled transition or slides into a crisis of cascading failures.
"If we get this right, there's still a chance," he says. "But we have to get it right now."
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Saitama Sinkhole: Are Road Collapses on the Rise?
Author: Daniel Manning
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