Tractor-trailers can scare drivers because of their size. If a driver is too close and a tractor-trailer’s driver jackknifes, that can easily result in a serious collision. If you’ve been hit by a driver who lost control in poor weather or due to poor driving, you may be considering turning to your attorney for help. Here’s some information on how a jackknife occurs, so you can use it in your case.

How does a jackknife happen?

A jackknife occurs when the trailer behind a tractor slides out of position into a “V” formation.

A jackknife can happen because of many reasons. For instance, if the rear wheels of the tractor locks, then the tractor will try to spin just like a normal vehicle would, fishtailing in the rear. However, because of how the truck is designed, the trailer will actually slide out of position first, entering into the dangerous “V” position.

If the trailer’s wheels lock, this can also result in a jackknife. The trailer will want to spin out, but because the trailer is long and heavy, it is slower than the tractor pulling it. This results in a swinging motion that starts to move into a jackknife position. Most of the time, if a driver notices this, a correction is possible to get the trailer back into position. This is unlike when the wheels lock on the tractor; when that happens, the trailer will collide with or quickly turn on the tractor, making it hard to correct.

Other drivers on the road should watch for high winds or tight curves in the road, because these can act as aggravating factors leading to a full “V” formation. If a trailer is starting to move to the side and the driver can’t correct it before it reaches around 15 degrees, then it is highly unlikely that the driver can recover the positioning necessary, leading to a crash and potentially collisions with other vehicles on the road.

Source:, “Tractor Trailer Jackknife,” accessed Feb. 19, 2016