The most dangerous times to drive in Illinois aren't when most crashes happen
Crash volume peaks at 3 PM on a Friday. Crash deaths peak after dark on the weekend. The gap between those two facts is the most useful thing in Illinois' crash data.
Illinois averages 833 crashes a day, but they are not spread evenly across it. Ask when crashes happen and the data points to mid-afternoon. Ask when crashes kill and the data points somewhere else entirely.
In 2024, the four deadliest hours on Illinois roads ran from 8 p.m. to midnight. Crashes in that window turned fatal at a rate of 7.30 per 1,000, about 3.4 times the rate of the morning errand hours. The overnight window that follows, midnight to 4 a.m., was nearly as bad at 6.69.
Meanwhile the window with the most crashes, noon to 4 p.m., sat near the bottom of the danger table at 2.70 fatal crashes per 1,000. Your fender-bender risk and your fatality risk live on opposite ends of the clock.
Here is the full picture from IDOT's 2024 statewide data, plus the hour-by-hour numbers for St. Clair County.
When Illinois crashes happen
The afternoon block and the evening commute together account for 47% of all Illinois crashes with a recorded time. This is a volume story: more cars, more conflict points, more crashes.
IDOT 2024 Crash Facts & Statistics. 303,288 of 303,913 crashes had a recorded time.
When crashes kill
Now the same six windows, measured by how often a crash in each one turns fatal. The curve flips. The 8 p.m. to midnight window produced 243 fatal crashes from just 33,269 total, the worst ratio of the day by a wide margin.
A crash between 8 p.m. and midnight is about 3.4 times more likely to be fatal than one between 8 a.m. and noon. Darkness, speed, and impairment do the work that traffic volume can't.
IDOT 2024 Crash Facts & Statistics. 303,288 of 303,913 crashes had a recorded time.
Rate = fatal crashes divided by total crashes in each window, per 1,000. Absolute fatal counts: 173, 123, 128, 194, 224, and 243 across the six windows.
Serious injuries split the difference
Incapacitating injuries, what IDOT calls A-injuries, peak with the evening commute. The 4 to 8 p.m. window produced 1,417 A-injury crashes in 2024, the most of any block, with the afternoon window second at 1,316.
So the commute hours own the serious-injury problem, and the night hours own the fatality problem. There is no window where the roads are actually forgiving. There are just different ways to lose.
The day-of-week paradox
The same volume-versus-lethality flip shows up across the week. Friday is Illinois' crash-volume champion with 50,004 in 2024. Sunday has the fewest crashes of any day, 35,315, and the most fatal ones, 201.
Put those together and a Sunday crash is twice as likely to be deadly as a Tuesday one, 5.69 fatal crashes per 1,000 against 2.84. Saturday runs second at 4.46. Weekend driving skims off the commuters and leaves a higher concentration of the trips that kill.
| Day ↕ | Total Crashes ↕ | Fatal Crashes ↕ | Fatal per 1,000 ↕ |
|---|---|---|---|
| Sunday | 35,315 | 201 | 5.69 |
| Monday | 42,522 | 149 | 3.5 |
| Tuesday | 45,125 | 128 | 2.84 |
| Wednesday | 43,673 | 133 | 3.05 |
| Thursday | 45,167 | 135 | 2.99 |
| Friday | 50,004 | 154 | 3.08 |
| Saturday | 41,482 | 185 | 4.46 |
IDOT 2024 Crash Facts & Statistics
Two details worth knowing
Found in the margins of the same IDOT tables.
The Metro East runs on the same clock
St. Clair County's hourly data tells the statewide story in miniature. Crashes climb all morning, peak in the school-pickup and early-commute window, 348 at 3 p.m. and 363 at 4 p.m., then fall off through the evening.
But look at where the county's 36 fatal crashes landed in 2023. The two busiest hours produced six of them combined. The four hours from 10 p.m. to 2 a.m., some of the quietest on the road, produced ten, and 3 a.m. alone added four more.
The weekly pattern matches too. Friday was the county's busiest crash day at 805, but Sunday, its quietest, carried 10 of the 36 fatal crashes. That is 28% of the deaths on about 12% of the crashes.
St. Clair County crashes by hour (2023)
IDOT County Summary Crash Report, St. Clair County, 2023 (the most recent year IDOT publishes county summaries)
What to do with this
The practical read is simple. Your daily commute is where the fender-benders and the serious-injury crashes live, so the boring advice still matters most: space, patience, and a phone you don't touch. The drive that deserves real thought is the optional one after 8 p.m. on a weekend.
And if a crash does happen, the clock matters there too. Late-night crashes are likelier to involve an impaired, uninsured, or fleeing driver, which makes the evidence collected in the first days more important, not less. The insurance company starts working on its version of events immediately. It's not fair, but it's how they operate.
Be a human first. Get checked out, even if you feel fine. Then talk to an attorney before you give any insurer a recorded statement. The consultation is free, and there is no fee unless we recover money for you.
Quick answers
What time do most car accidents happen in Illinois?
Between noon and 4 p.m. Illinois recorded 71,750 crashes in that window in 2024, the most of any four-hour block, with the 4 to 8 p.m. evening commute close behind at 70,841. Together those two windows account for 47% of all crashes with a recorded time.
What is the most dangerous time to drive in Illinois?
By fatality rate, 8 p.m. to midnight. Crashes in that window were fatal at a rate of 7.30 per 1,000 in 2024, about 3.4 times the mid-morning rate. The overnight window from midnight to 4 a.m. is nearly as dangerous at 6.69 per 1,000.
What is the most dangerous day of the week to drive?
Sunday, by fatality rate. Sunday had the fewest total crashes of any day in Illinois in 2024 (35,315) but the most fatal crashes (201). That works out to 5.69 fatal crashes per 1,000, twice Tuesday's rate of 2.84.
When do most crashes happen in St. Clair County?
In 2023, the most recent year IDOT publishes county summaries, St. Clair County crashes peaked between 3 and 5 p.m., with 3 p.m. (348 crashes) and 4 p.m. (363) the two worst hours. Friday was the busiest day at 805 crashes, but Sunday had the most fatal crashes, 10 of the county's 36.
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Sources and methodology
Statewide figures are final 2024 data from IDOT's 2024 Illinois Crash Facts & Statistics. Fatality rates are computed as fatal crashes divided by total crashes in each time or day bucket, per 1,000; crashes without a recorded time (625 of 303,913) are excluded from time-based rates. St. Clair County figures are from IDOT's 2023 County Summary Crash Report, the most recent county-level summary IDOT publishes. This article is for informational purposes only and does not constitute legal advice.