Remember the last time you drove down a street in Indianapolis without swerving to avoid a pothole? Can you drive to work or to the grocery store without telling yourself or perhaps a passenger in the car about the size of a particular pothole? Maybe you said it was a crater rather than a hole (I know I have).
Indiana has a pothole problem.
A recent study by QuoteWizard, a site that sells Lending Tree insurance, examined pothole-related web searches and repair requests. It turns out that Indiana ranked second nationwide for where road craters are causing the most problems.
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Potholes appear to be more of an infrastructure problem than an environmental problem. And without a doubt, deteriorating infrastructure is at the heart of Indianapolis’ pothole woes, compounded by tight budgets and overworked staff. In fact, Mayor Hogsett and the Department of Public Works have authorized overtime for road maintenance crews to fill potholes across the city this spring.
Still, environmental factors play a role—and maybe even more than you might think. This hybrid (no pun intended) is exactly what we’ll be looking at for this week’s Scrub Hub.
We investigate the questions: How does climate change affect potholes? And does it make pothole problems worse?
To find the answers, we spoke to someone at the city’s Public Works Department and looked at what the research says about pesky potholes.
Short answer: cracks to potholes to craters
To understand how climate change can affect potholes, it’s important to understand what causes them in the first place. Despite what many may think, it’s not just about old roads crumbling. Instead, it is the result of the weather.
Just as our bodies feel a little stiffer in winter, roads have a similar problem. As temperatures cool, asphalt becomes less flexible, making it more prone to cracking.
When moisture gets into cracks and freezes, it expands. Then, when temperatures get a little warmer and the ice thaws, it contracts—simple physics.
As this freeze-thaw cycle continues, the cracks grow larger and pockets form in the asphalt. After that, it doesn’t take much for the surface to crumble when a nearly two-tonne car drives over it. Other cars kick up the debris and erode the edges as they drive over it, creating a pothole.
Potholes are possible on both asphalt and concrete roads, the latter being more wear-resistant while asphalt is more susceptible to the conditions that cause potholes. And the vast majority of roads in Marion County are paved, according to DPW spokesman Ben Easley.
“It’s the temperatures above and below freezing in a single day that really ruin the roads,” he said.
Since early December 2021, the Indianapolis area has experienced at least 36 days when the temperature has fluctuated above and below 32 degrees Fahrenheit in a 24-hour period, according to an IndyStar review of data from the National Oceanic and Atmospheric Administration. That’s nearly a quarter of the city’s winter days ripe for trouble.
Long answer: climate change will make the problems worse
Indianapolis and the state as a whole experienced winters in which the temperature fell below freezing and stayed there or hovered just above. Those were the good days, Easley said.
However, the consistently colder days seem to be becoming increasingly rare as the effects of climate change are felt across the country and here in Indiana.
Forecasts of climate change for the next few decades suggest pothole problems will become even more common in Midwestern cities, according to research. Most freeze-thaw cycles have historically occurred in places like Missouri, but frequency will decrease in those areas as these cycles move north.
Studies by the Purdue Climate Change Research Center indicate that Indiana is experiencing greater temperature swings and fewer very cold days compared to decades ago, and this trend is not expected to increase until mid-century. Climate change also brings with it greater amounts of precipitation, particularly wetter winters with much more rain than snow.
Such weather is absolutely right – or wrong – to produce potholes.
“Conditions are much more regular for potholes than they used to be,” Easley said. “This freeze-thaw cycle, along with additional precipitation, is eroding the roads.”
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So far this year, DPW has filled more than 169,000 potholes across Indianapolis. According to Easley, the city received more than 27,000 pothole service requests in 2022.
However, it is difficult to deduce from the data whether climate change is leading to more pothole inquiries, since the reporting system is only a few years old and therefore cannot show any long-term trends. It also counts the number of calls or inquiries submitted rather than the number of potholes reported.
That being said, DPW acknowledges the link between climate and road conditions (but stresses they are not climatologists).
A 2017 US Department of Transportation report supports these predictions, saying increases in average winter air temperatures are likely to affect freeze-thaw cycles and road infrastructure. It added that areas with more winter days above freezing may need to adjust or expand weight limits on roads.
Indianapolis isn’t the only place experiencing these issues. So does Kansas City, Boston and others.
So what can be done to try to prevent these pothole problems, especially as they are likely to get worse?
The city regularly assesses the needs of its roads to determine where it can fill potholes first and which roads require more extensive work. As a middle ground, Indianapolis has done more strip patching over the past five years. There it will lay a new surface along an extensive stretch of road with considerable problems.
DPW is also working to improve the base course of regularly traveled roads when they are demolished for major construction projects — that’s happening with the work on Delaware Street in downtown Indy, Easley said.
While concrete is more resistant to potholes, it is also more expensive, and many city households cannot afford to cover all roads like this.
Because of this, many of the city’s engineers are keeping their ears open and fingers crossed for new technologies and advances that will help keep the streets of Indianapolis food-free. A concrete that can heal itself, anyone? It might not be that far fetched.
If you have further questions about climate and infrastructure or other topics, let us know! You can ask us questions by submitting a question using our Google form below.
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Call IndyStar reporter Sarah Bowman at 317-444-6129 or email email@example.com. keep following her Twitter and Facebook: @IndyStarSarah. Connect with IndyStar’s environmental reporters: join The Scrub on Facebook.
IndyStar’s environmental reporting project is made possible through the generous support of the nonprofit Nina Mason Pulliam Charitable Trust.