# Jackknife Accident

*Last updated: 2026-06-25*

> A jackknife accident occurs when a tractor-trailer folds sharply on itself so that cab and trailer form an acute angle, resembling an open pocketknife.

A jackknife accident occurs when a tractor-trailer folds sharply on itself so that cab and trailer form an acute angle, resembling an open pocketknife. The typical trigger is sudden braking on a low-grip surface, aquaplaning, or excessive speed through a curve: the tractor's drive wheels lock or lose traction while the heavier trailer continues forward, pushing the tractor's rear sideways. The combination becomes uncontrollable within fractions of a second, liable to sweep into oncoming lanes or roll over. Jackknife accidents rank among the most severe incident types in road freight transport. Key preventive measures are regular brake maintenance, correct tyre condition, proper load distribution, and driver training in emergency braking techniques, with electronic stability systems providing an additional layer of protection.

**Source:** [https://en.wikipedia.org/wiki/Jackknifing](https://en.wikipedia.org/wiki/Jackknifing)

## Quick Facts

| Property | Value |
|---|---|
| Term | Jackknife Accident |
| Language | EN |
| Word count | 121 |
| Last updated | 2026-06-25 |
| Source | https://en.wikipedia.org/wiki/Jackknifing |

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