Highways to Avoid When in Illinois According to 5 Years of Crash Data

Key Takeaways

• Cook County appears most often as the location of the “worst mile” on Illinois’ most dangerous highways.
• The I-255 is Illinois’ most dangerous highway overall, with crashes here twice as likely to turn deadly as the average Illinois interstate.
• The I-57 recorded the most total deaths of any highway in our study, concentrated in rural, high-speed stretches downstate.
• The I-290 has the highest crash rate of any highway we studied, packing nearly 20,000 crashes into just 30 miles.
• Truck traffic is a major risk factor on highways like the I-80 and I-70, where trucks make up close to or over a third of daily vehicles.

More than 1,000 people die on Illinois roads every year, and we wanted to know exactly which highways are putting drivers at the greatest risk. The Chicago accident attorneys at Walner Law analyzed five years of crash data across 19 Illinois interstates to find out.

Here’s what we found: I-255 is the most dangerous highway in Illinois, turning fatal at twice the rate of a typical Illinois interstate. I-57 recorded the most total deaths of any highway in the state. And on I-70, nearly 40% of the vehicles sharing the road with you are trucks.

How We Ranked Illinois’ Most Dangerous Highways

We examined 19 Illinois interstates using five years of state crash data (2021-2025). To measure real danger rather than raw crash counts, we calculated deaths per 100 million vehicle miles traveled, which accounts for how much a highway is actually used. We also looked at:

• How often crashes happen per 100 million vehicle miles
• What share of those crashes turn fatal
• What percentage of each highway’s traffic is made up of trucks
• Total deaths, crashes, and injuries recorded from 2021 to 2025

We excluded any highway with too little traffic to produce statistically reliable results.

Illinois’ 5 Most Dangerous Highways, Ranked 

You can access the complete research findings here.

Illinois’ 5 Most Dangerous Highways, Ranked

1. I-255 — Most Dangerous Highway in Illinois

The takeaway: A crash on I-255 is more than twice as likely to kill you as a crash on the average Illinois interstate.

• Length: 27 miles
• Location: South of St. Louis, along the Illinois side of the Mississippi River
• Deaths per 100M vehicle miles: 0.78
• Crashes per 100M vehicle miles: 65.8
• Total deaths (2021–2025): 17
• Total crashes (2021–2025): 1,400
• Total injuries (2021–2025): 377
• Average daily vehicles: 43,900
• Deadliest county: St. Clair (6 deaths in a single mile)

I-255 is short (under 30 miles) but it punches far above its weight in fatality risk. Every recorded death on this stretch happened in an urban area, and the crash-to-fatality ratio is the worst of any interstate in the state. One mile in St. Clair County alone accounts for six of the highway’s 17 deaths over five years.

2. I-57 — Deadliest Rural Highway in Illinois

The takeaway: More people have died on I-57 than on any other Illinois interstate, most of them on open rural stretches.

• Length: 353 miles
• Setting: Rural, downstate Illinois
• Deaths per 100M vehicle miles: 0.75
• Crashes per 100M vehicle miles: 87
• Total deaths (2021–2025): 133
• Total crashes (2021–2025): 15,400
• Total injuries (2021–2025): 4,000
• Average daily vehicles: 27,600
• Deadliest county: Cook

I-57’s length makes it Illinois’ deadliest highway by raw death count. Over 65 of its 133 fatalities happened on rural, high-speed stretches, where crashes are more severe and help takes longer to arrive.

3. I-290 (Eisenhower Expressway) — Highest Crash Rate in Illinois

The takeaway: No Illinois highway packs more collisions per mile than the Eisenhower, about 11 crashes a day on a road just 30 miles long.

• Length: 30 miles
• Location: Chicago (Cook County)
• Deaths per 100M vehicle miles: 0.70
• Crashes per 100M vehicle miles: 242
• Total deaths (2021–2025): 58
• Total crashes (2021–2025): 19,900
• Total injuries (2021–2025): 3,300
• Average daily vehicles: 151,100
• Deadliest county: Cook

Nearly 20,000 crashes in five years, compressed into 30 miles, works out to roughly 11 collisions every single day. Every recorded death occurred in an urban setting, making I-290 the most crash-dense highway in the state.

4. I-94 — Highest Traffic Volume of Any Dangerous Illinois Highway

The takeaway: I-94 sees more traffic, more crashes, and more nighttime deaths than any other highway on this list.

• Route: Through Chicago
• Deaths per 100M vehicle miles: 0.61
• Crashes per 100M vehicle miles: 182
• Total deaths (2021–2025): 135
• Total crashes (2021–2025): 40,000
• Total injuries (2021–2025): 6,900
• Average daily vehicles: 159,800
• Deadliest county: Cook

I-94 carries the most traffic of any highway studied, nearly 160,000 vehicles a day, and posted the highest crash total in the state: 40,000 collisions in five years. More than 70% of its fatalities happened after dark.

5. I-70 — Heaviest Truck Traffic in Illinois’ Top 10

The takeaway: Almost 4 in 10 vehicles on I-70 are trucks, raising the danger for everyone else on the road.

• Length: 163 miles
• Truck share of traffic: ~40%
• Deaths per 100M vehicle miles: 0.60
• Crashes per 100M vehicle miles: 60
• Total deaths (2021–2025): 54
• Total crashes (2021–2025): 5,400
• Total injuries (2021–2025): 1,300
• Average daily vehicles: 30,400
• Deadliest county: St. Clair (8 deaths)

No highway in the top 10 has a heavier truck presence than I-70. That mix of high-speed passenger vehicles and heavy trucks is a major factor behind its 54 deaths over five years, with St. Clair County recording the worst single stretch.

Why Truck Traffic Makes Illinois Highways More Dangerous

Jonathan Walner, Managing Attorney at Walner Law, weighed in on what these numbers mean for everyday drivers:

“I’ve spoken to hundreds of people who’ve been in serious highway crashes involving trucks, and the ones involving trucks almost always come back to the same thing. On highways like the I-80 and I-70, where nearly a third of all traffic is trucks, the biggest mistake regular drivers make is hanging in a truck’s blind spot. If you can’t see the driver’s mirrors, they can’t see you. Pass quickly and get clear. And at night, stay at least five or six car lengths back. Truck drivers can’t react as fast in the dark, and the stopping distances are much longer than most people think.”

Injured in a Crash on One of Illinois’ Most Dangerous Highways?

If you or someone you love was hurt in a crash on the I-255, I-57, I-94, or any other Illinois highway, we’re here to help. Contact our Chicago car accident lawyers today for a free, no-obligation consultation.

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Methodology note: Deaths and crashes per 100 million vehicle miles were calculated by dividing total fatalities and total crashes by total distance driven on each highway over the five-year study period (2020-2025). Highways with insufficient traffic data were excluded to ensure statistical reliability.