Two behaviors stand out in the 36,297 fatal crashes on U.S. roads in 2024, according to a new study of national traffic data from The Schiller Kessler Group. Alcohol impairment, defined as a driver with a blood alcohol concentration of 0.08% or higher, was a factor in 29.8% of fatal crashes, and speeding was a factor in 28.1% (10,203 crashes). Together, they are the country’s leading behavioral causes of deadly collisions. Speeding is common across the country: in 25 states and the District of Columbia, speeding was involved in more than 30% of fatal crashes. The study also tracked distraction, which was linked to 8.2% of fatal crashes nationally. Distraction is hard to confirm after a crash, though, and experts believe the true share is likely much higher.
State by state, the data shows some unexpected leaders. Vermont is the only state in the top ten for both speeding and drunk driving. Speeding was involved in 50.9% of its 53 fatal crashes, and alcohol in 43.4%, the highest impairment rate in the country. Alaska ranks second for speeding (47.6%). Hawaii and Wyoming follow at 41.2% each, and Montana ranks high on both measures, with 43% for speeding and 35.8% for alcohol. Alcohol related crashes aren’t limited to small, rural states. Texas had an alcohol impairment rate of 39.8% (1,503 of 3,774 fatal crashes) and South Carolina had 39.7% (376 of 948). Ohio (36.2%), Kansas (35%), Oklahoma (35%), and Iowa (34.9%) also ranked high.
At the other end, Florida had the lowest speeding rate in the country at 10.7%, and New Jersey had the lowest alcohol impairment rate at 21.8%. North Carolina reported the lowest distraction rate at 1.4%, even though it ranks sixth for speeding. Hawaii (38.1%) and New Mexico (37%) reported the highest distraction rates. The study notes that such a wide range likely reflects differences in how states record distraction rather than real differences in driver behavior. Mississippi stands out most. It has the highest fatal crash rate (23.04 per 100,000 residents) and the highest fatality rate (25.59 per 100,000) in the country. Yet its rates for speeding (17.3%), alcohol impairment (22.7%), and distraction (2.5%) are all below the national averages. That suggests Mississippi’s high death toll comes from other factors, such as road infrastructure, emergency response times, seat belt use, or older vehicles.
Age shows some of the clearest patterns in the study. Speeding was involved in 47.4% of traffic deaths among 16 to 20-year-olds, the highest share of any age group. The share was 42.2% for 21 to 24-year-olds, then fell steadily with age to 36.5%, 29.9%, 26.2%, 19.6%, 17.1%, and finally 14.1% for people 75 and older. Alcohol peaks a little later. The share of deaths involving impairment rises from 22% for those under 16 to 31% for 16- to 20-year-olds and reaches 41% for both 21 to 24 and 25 to 34-year-olds. It then declines through each older group to 12% for people over 75. Distraction peaks at 11.4% for drivers under 16, stays around 7% to 8% through the middle age groups, and rises again to 9% for 65 to 74-year-olds and 9.3% for those 75 and older.
People aged 25 to 34 accounted for the most traffic deaths, 6,921 (17.6%), followed by 35 to 44-year-olds with 6,252 (15.9%). Together, those two groups make up 33.5% of all traffic deaths. Adults 55 and older account for a similar share, with 13.4% aged 55 to 64, 10.5% aged 65 to 74, and 9.9% aged 75 and older. Older adults are far less likely to be speeding or impaired in fatal crashes. The study attributes their high death share mainly to greater physical vulnerability in a crash rather than to risky driving.
The time of year also matters. Fatal crashes were lowest in January (2,538) and February (2,498), then rose steadily to a peak in October (3,369), with August (3,342) and September (3,277) close behind. Deaths followed the same curve, rising from 2,710 in February to 3,620 in October. The data partly supports the well-known “100 Deadliest Days” between Memorial Day and Labor Day, when vacation travel, new teen drivers, and summer gatherings add to road risk. It also suggests the danger continues into fall, as days get shorter.
The study also shows that a state’s average can hide big local differences. Florida ranks tenth safest overall and lowest in the country for speeding deaths. Yet Palm Beach County averaged 1.12 deaths per fatal crash in 2024 (214 deaths in 191 crashes), well above the national average of 1.08. By comparison, Miami-Dade averaged 1.05, Broward 1.06, and Orange and Hillsborough counties 1.04 each. All of these counties share the same statewide enforcement priorities, which suggests that local conditions such as high-speed corridors, seasonal tourist traffic, longer trips, or an older driver population can make crashes more severe in some counties than in others.
