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Jackknife

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Jackknife truck accident data concern a particular event involving a combination vehicle in motion. In the United States, NHTSA's Fatality Analysis Reporting System recorded 133 large trucks as jackknifed in 2024, alongside a separate count of 2,869 truck-tractors in fatal crashes. These national illustrative figures cover the 50 states and the District of Columbia. They describe vehicles involved in fatal crashes, rather than all jackknife events or people killed. The 2024 figures come from the FARS Annual Report File, and the columns represent different vehicle selections.[1][2][3][4][5][6][7][8]

Contents

Official definition

The FARS Analytical User's Manual, 1975-2024, defines jackknife as uncontrolled articulation between a moving combination vehicle's power unit and its trailer or trailers. The trailer ceases to track directly behind the power unit, and the driver did not initiate that non-tracking situation. Data element V22, Jackknife, records whether the event occurred during the unstabilized situation. This official definition concerns movement during the event. The manual cautions that a vehicle found resting in a jackknife position has not necessarily experienced a jackknife as defined by this element.[1][2][3][4][5][6][7][8]

National figures

The national illustrative series selects large trucks recorded as jackknifed in NHTSA FARS fatal crashes. It reports 170 trucks in 2020, 129 in 2021, 159 in 2022, 153 in 2023 and 133 in 2024. Among these supplied years, the highest count of large trucks recorded as jackknifed was 170 in 2020, and the lowest was 129 in 2021. The separate truck-tractor series counts truck-tractors in fatal crashes. Its different vehicle population means that column should not be treated as a denominator for the large-truck jackknife counts.[1][2][3][4][5][6][7][8]

National figures[1][2][3][4][5]
YearLarge trucks recorded as jackknifedTruck-tractors in fatal crashes
20201702,883
20211293,417
20221593,355
20231533,086
20241332,869

United States, 50 states and the District of Columbia. 2024 is the FARS Annual Report File.

What the term does not tell you

These figures do not measure how often jackknifing occurs across all truck travel or across crashes of every severity. FARS has a fatal-crash-only scope, and the supplied counts select vehicles, not deaths or distinct crashes. No population rate is supplied. The operational selection of large trucks recorded as jackknifed must also remain distinct from the definition itself: an angled resting position alone does not establish the event. Neither the definition nor these national counts identifies why a particular event occurred.[1][2][3][4][5][6][7][8]

On related publications

References

  1. abcde "Fatality Analysis Reporting System (FARS) 2020 national data files (Final File)". National Highway Traffic Safety Administration. Official source. Checked . Source record
  2. abcde "Fatality Analysis Reporting System (FARS) 2021 national data files (Final File)". National Highway Traffic Safety Administration. Official source. Checked . Source record
  3. abcde "Fatality Analysis Reporting System (FARS) 2022 national data files (Final File)". National Highway Traffic Safety Administration. Official source. Checked . Source record
  4. abcde "Fatality Analysis Reporting System (FARS) 2023 national data files (Final File)". National Highway Traffic Safety Administration. Official source. Checked . Source record
  5. abcde "Fatality Analysis Reporting System (FARS) 2024 national data files (Annual Report File)". National Highway Traffic Safety Administration. Official source. Checked . Source record
  6. abcd "Fatality Analysis Reporting System Analytical User's Manual, 1975-2024 (DOT HS 813 794)". National Highway Traffic Safety Administration. Official source. Checked . Source record
  7. abcd "Large trucks: 2024 data (DOT HS 813 816, June 2026)". National Highway Traffic Safety Administration. Official source. Checked . Source record
  8. abcd "Overview of motor vehicle traffic crashes in 2024 (DOT HS 813 791, April 2026)". National Highway Traffic Safety Administration. Official source. Checked . Source record