What causes the most traffic deaths?

Alcohol-impaired driving (BAC 0.08+) is one of the most consistent killers on American roads, involved in approximately 30% of all traffic fatalities year after year. In raw numbers, that translates to roughly 10,000–13,000 deaths annually, a toll that has been stubbornly persistent despite decades of public awareness campaigns, ignition interlock requirements, and DUI enforcement.

FARS data reveals a strong pattern by time of day: alcohol-impaired fatal crashes are dramatically concentrated at night, particularly between 9 PM and 3 AM on weekends. Nearly half of all nighttime fatal crashes involve an impaired driver. Rural areas also see disproportionate alcohol-impaired fatalities, lower enforcement density and longer drive distances to bars and restaurants contribute to the risk.

Drug impairment (marijuana, opioids, stimulants) is a growing but harder-to-measure category. NHTSA has expanded toxicology testing requirements over the years, and recent FARS data shows increasing drug involvement in fatal crashes, often in combination with alcohol. The legal and behavioral landscape for drug-impaired driving is evolving faster than the measurement systems that track it.

Browse alcohol-impaired crash data by state on the causes page, or see how your state compares on the states overview.

Speeding

Speeding contributes to roughly 29% of US traffic fatalities, approximately 11,000–12,000 deaths per year. NHTSA defines speeding-related crashes as those where the driver was cited for a speed violation, was racing, or was traveling too fast for road conditions even if below the posted limit. That last category matters: many fatal crashes occur when drivers fail to reduce speed for wet roads, fog, ice, curves, or work zones.

The physics of speeding are unforgiving. At 40 mph, stopping distance increases by roughly 35% compared to 30 mph. At 60 mph, kinetic energy is four times what it is at 30 mph. Higher speeds not only increase crash likelihood, they drastically increase the probability that any crash becomes fatal. The difference between a survivable crash and a fatal one is often measured in a handful of mph.

Speeding is most lethal on rural two-lane highways with high posted limits and limited median separation. States like Wyoming, Montana, and North Dakota, with extensive high-speed rural networks, tend to show higher speeding-related fatality shares than dense urban states. Compare state-level speeding data on the rankings page.

Distracted Driving

FARS records distracted driving fatalities in roughly 8–10% of all fatal crashes, but this number is widely acknowledged to be an undercount. Distraction is self-reported by surviving drivers and witnesses, and few people admit to phone use at crash scenes. Post-crash phone record analysis is not systematically conducted. NHTSA and transportation researchers generally believe the true distraction contribution to fatal crashes may be two to three times what appears in FARS.

Distracted driving encompasses visual distraction (looking away from the road), manual distraction (hands off wheel), and cognitive distraction (mind off driving). Texting while driving combines all three. At highway speed, a five-second look at a phone covers the length of a football field with no eyes on the road. Young drivers (ages 15–29) are overrepresented in distraction-related fatal crashes, but the behavior is pervasive across all age groups.

Hands-free laws have not proven sufficient to eliminate the risk: cognitive distraction persists even when the driver's hands are on the wheel. NHTSA's research suggests that hands-free phone conversations create comparable cognitive load to handheld calls, though they eliminate the visual and manual distraction components.

Pedestrian Fatalities

Pedestrian deaths are a growing crisis in US traffic safety. After declining through the 1990s and early 2000s, pedestrian fatalities rose sharply from 2009 onward. By 2022, approximately 7,500 pedestrians were killed on US roads, the highest annual count in decades. As a share of total traffic deaths, pedestrians now represent roughly 17–18%, up from around 11–12% in the mid-2000s.

FARS data shows that pedestrian fatalities are heavily concentrated at night (76% in darkness), on arterial roads with high speed limits, and in urban areas without adequate sidewalks, crosswalks, or pedestrian signal phases. The rise in SUV and pickup truck market share is directly implicated: frontal profiles of taller vehicles strike pedestrians in the torso and head rather than the legs, creating more fatal outcomes at the same speeds.

Older adults (65+) are disproportionately represented in pedestrian fatalities relative to their share of walking activity. They cross more slowly, are harder for drivers to see at night, and are more vulnerable to fatal injury from any impact. Explore pedestrian cause data on the causes page or see which states have the highest rates on the Safest Roads guide.

Unrestrained Occupants

Seatbelts save lives at a rate matched by almost no other traffic safety intervention. NHTSA estimates that seatbelts save approximately 14,000–15,000 lives per year. Yet in 2022, over 13,000 people who died in traffic crashes were unrestrained, roughly 37–40% of all occupant fatalities. That means thousands of deaths annually occur in crashes that seatbelts would very likely have prevented or mitigated.

FARS shows clear patterns in who is unrestrained: pickup truck occupants use seatbelts at lower rates than passenger car occupants; nighttime crashes have much higher unrestrained fatality rates than daytime crashes; and rural crashes involve unrestrained occupants more often than urban crashes. Males have significantly lower belt use rates than females across all age groups.

States with primary enforcement laws, where police can stop vehicles solely for a seatbelt violation, consistently achieve higher belt use rates (often 90%+) than states with secondary enforcement (belt use often 80–85%). The gap in unrestrained fatality rates between high-use and low-use states is measurable and statistically significant in FARS data. See how your state compares across cause categories on the state data pages.

Cause Data Summary

Categories are not mutually exclusive. Source: NHTSA FARS 2018–2022.

Compiled by the PlainRoadSafety research team.

Frequently Asked Questions