Interstate Deaths by State: Rates, Routes and Counties, 2020 to 2024

States ranked by Interstate deaths per 100 miles

Six states are at 18 or more deaths per 100 Interstate miles a year: Delaware at 22.2, Florida at 20.5, California at 19.8, Georgia at 18.2, Connecticut at 18.1 and Rhode Island at 18.0. Across all 48 states, crashes on main Interstate mainlines killed 20,668 people from 2020 to 2024. That works out to 9.8 deaths per 100 miles a year, and 19 states are above it.

The ranking covers Interstates only. Most lists of the most dangerous states for driving count deaths on every road and divide by population or by miles traveled, a separate question with a separate answer. On that all-roads basis, IIHS put Mississippi highest in 2024 at 25.6 deaths per 100,000 people and Rhode Island lowest at 4.7. On Interstates per mile, Mississippi ranks 18th at 10.9 and Rhode Island 6th. The all-roads numbers for every state are in our traffic deaths by state table.

State miles count shared pavement once. Where two Interstates run on the same road, as I-20 and I-59 do across much of Alabama, the FHWA Route Log books those miles to only one of the two, and we add up those rows. Each crash counts under the one route named in its FARS trafficway field, so a death on the shared section also counts once. Lettered branches such as I-35E and I-35W in Texas are part of their state's total.

Delaware and Rhode Island rank high on small counts: 26 and 39 deaths in five years. One death moves Delaware's rate by 0.9 and Rhode Island's by 0.5, and five fewer deaths would drop Delaware to 17.9, below five other states. The rate is also blind to traffic. It divides deaths by miles of road, so a crowded urban state and an empty rural one are compared on pavement alone.

Each state's deadliest Interstate, by rate and by deaths

The highest route rates in any state are on I-95 in Pennsylvania and Florida, both at 30.8 deaths per 100 miles a year. Pennsylvania's figure covers 41.53 miles around Philadelphia and Florida's covers 381.93. Three more state stretches top 28: the Illinois part of I-94 (28.4), the Texas part of I-69 (28.3) and the California part of I-10 (28.2).

A deadly route can sit inside a low-ranked state, because the statewide rate spreads deaths over every rural mile too. Pennsylvania ranks 32nd overall at 6.1 and New York 42nd at 3.5, yet New York's 23.47 miles of I-95 run at 23.0.

In Florida, I-95's rate is higher than that of I-4, the road a widely shared 2021 Teletrac Navman ranking, based on 2016 to 2019 data, called the most dangerous highway in the country. I-4 had 167 deaths on 131.89 miles, 25.3 per 100 miles a year, the second highest rate of any whole Interstate. Florida's I-95 had 588 deaths at 30.8.

Route rates use each route's own miles in the state, counting pavement it shares with another route, so they match the figures on our route guides and do not add up to the state rate. A route needs at least 20 miles in the state and 100 miles in all to get a rate. That rule leaves out Louisiana's I-12, 86.65 miles long, whose 99 deaths work out to 22.9, above I-10's 18.1 in the table. The most-deaths column is a raw count that favors long routes: I-5 in California had 735, the most of any route in one state.

The county with the most Interstate deaths in each state

San Bernardino County, California had more Interstate deaths than any other county from 2020 to 2024, 374. Harris County, Texas had 350 and Dallas County, Texas 337, then San Diego County at 290 and Los Angeles County at 263, both in California. Outside Texas and California, Cook County, Illinois led with 253 and Maricopa County, Arizona followed at 235.

In a few states one county holds a large share. Clark County had 119 of Nevada's 220 Interstate deaths, 54.1%, and Cook County had 34.7% of Illinois's. All 26 of Delaware's deaths were in New Castle County, and Providence County had 18 of Rhode Island's 39.

These are plain totals with no adjustment for a county's size, Interstate miles or traffic. In rural states a few crashes decide the top spot: Pennington County leads South Dakota with 12 deaths, and Windsor County leads Vermont with 11.