Scrub Hub: Is climate change making Indianapolis' pothole problems even worse?

Do you remember the last time you drove down an Indianapolis road without swerving to avoid a pothole? Can you drive to work or the store without commenting to yourself, or maybe a passenger in the car, about a particular pothole’s size? Maybe you said it was more of a crater than a hole (I know I have).

Indiana has a pothole problem.

A recent study from QuoteWizard, a site that sells insurance by Lending Tree, looked at pothole-related internet searches and repair inquiries. It found that Indiana ranked second across the country for where the road craters are causing the most issues.

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Potholes may seem like an infrastructure issue rather than an environmental one. And without doubt, deteriorating infrastructure is at the core of Indianapolis’ pothole woes, compounded by limited budgets and stretched staffing. In fact, Mayor Hogsett and the Department of Public Works have approved overtime for street maintenance crews to work on filling potholes around the city this spring.

Potholes and street deterioration along Carrollton Avenue on Tuesday, Oct. 26, 2021, in the Kennedy King neighborhood of Indianapolis.

All that said, environmental factors do play a role — and perhaps even more than you might think. That intersection (no pun intended) is exactly what we will be looking at for this week’s Scrub Hub.

We will explore the questions: How does climate change impact potholes? And is it making the pothole problems worse?

To find the answers, we spoke with someone from 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 may be impacting potholes, it’s important to know what causes them in the first place. Despite what many may think, it’s not just an issue of old roads breaking down. Instead, it’s the result of the weather.

Just as our bodies might feel a bit stiffer in the winter, roads have a similar problem. When the temperatures cool down, asphalt becomes less flexible, which makes it more susceptible to cracks.

When moisture gets into cracks and freezes, it expands. Then when temperatures warm a bit and the ice thaws, it contracts — simple physics.

As that freeze-thaw cycle continues, it makes the cracks bigger and creates pockets in the asphalt. After that, it doesn’t take much for the surface to crumble when a nearly two-ton car drives over it. Other cars disperse the rubble and erode away at the edges as they drive over it — and thus a pothole is created.

Potholes and street deterioration along Carrollton Avenue on Tuesday, Oct. 26, 2021, in the Kennedy King neighborhood of Indianapolis.

Potholes are possible in both asphalt and concrete roads, the latter are more durable to wear and tear while asphalt is more susceptible to the conditions that cause potholes. And the vast majority of roads in Marion County are asphalt, according to DPW spokesman Ben Easley.

“It’s the over and under freezing temperatures in a single day that really undoes the streets,” he said.

Since the beginning of December 2021, the Indianapolis area has seen at least 36 days during which the temperature swung 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 that are ripe to cause problems.

Long answer: Climate change will make problems worse

Indianapolis and the state as a whole used to see winters where the temperature dropped below freezing and stayed there or hovered just above it. Those were the good days, Easley said.

However, the consistently colder days seem to be coming fewer and farther in between as the effects of climate change are felt across the country and here in Indiana.

Climate change projections over the next few decades suggest that pothole problems will become even more prevalent in Midwestern cities, according to research. The most freeze-thaw cycles have historically happened in places like Missouri, but the frequency will become less in those areas as those cycles are moving north.

A pothole is blocked from traffic on a sideroad near U.S. 31 on Indianapolis' south side on Sunday, March 15, 2020.

Studies out of the Purdue Climate Change Research Center show that Indiana is seeing greater fluctuations in temperature and fewer very cold days compared to decades ago, and that trend is only expected to increase by mid-century. Climate change also is bringing about greater amounts of precipitation, especially wetter winters with much more rain instead of snow.

Such weather is totally right — or wrong — for producing potholes.

“The conditions are right for potholes much more regularly than they used to be,” Easley said. “That freeze-thaw cycle on top of additional precipitation is undermining the streets.”

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So far this year DPW has filled more than 169,000 potholes across Indianapolis. There also have been more than 27,000 pothole service requests submitted to the city in 2022, according to Easley.

Still, it’s hard to draw conclusions from the data on whether climate change is leading to more pothole requests because the reporting system is only a few years old and thus unable to show long-term trends. It also counts the number of calls or requests submitted rather than the number of potholes being reported.

That aside, DPW acknowledges the connection between climate and road conditions (but stresses they are not climatologists).

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A 2017 report from the U.S. Department of Transportation supports these predictions and says increases in average air temperatures during the winter are likely to influence freeze-thaw cycles and road infrastructure. It added that those areas experiencing more winter days above freezing may have to adjust or extend weight restrictions on roads.

Indianapolis is not the only place experiencing these problems. So too are Kansas City, Boston and others.

So what can be done to try to prevent these pothole problems, especially as they are predicted to get worse?

The city is regularly assessing the needs of its roads to determine where it can fill a pothole for the time being and what roads need more extensive work. As a middle-ground, Indianapolis has completed more strip-patching in the last five years. That’s where it will lay a new surface along an extended section of road with significant problems.

As a vehicle moves by on Forest Manor Avenue, Mayor Joe Hogsett, left, speaks during a press conference Thursday, May 13, 2021 about the next phase of Circle City Forward. A $25 million investment will be made in residential streets. Forest Manor Avenue is one of the streets that would see improvement.

DPW also is working to improve the base layer of regularly-traveled roads when they are torn up for larger construction projects — that’s what’s happening with the work on Delaware Street in downtown Indy, Easley said.

While concrete is more resilient to potholes, it also is more expensive and many city budgets can’t afford to surface all its streets that way.

That’s why many of the city’s engineers are keeping their ears open and fingers crossed for new technologies and advances that will help keep Indianapolis’ streets cater-free. A concrete that can heal itself, anyone? It may not be that far-fetched after all.

If you have more questions about climate and infrastructure, or any other topics, let us know! You can ask us by submitting a question through our Google form below.

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Call IndyStar reporter Sarah Bowman at 317-444-6129 or email at Follow her on 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.

This article originally appeared on Indianapolis Star: Climate change will make Indianapolis' pothole problems even worse