When is a truck most likely to jackknife loaded over loaded or empty?

When the wheels of a trailer lock up, the trailer will tend to swing around. This is more likely to happen when the trailer is empty or lightly loaded. This type of jackknife is often called a "trailer jackknife." See Figure 6.2.

1. What causes a truck to jackknife?
2. How does Jack knifing happen?
3. What is meant by jack knifing?

What causes a truck to jackknife?

When the brakes on a semi-truck are not working properly, it may cause the axles to lock-up. In these instances, the truck is dragging the trailer with locked brakes, which can push the trailer out to the side of the cab, causing the truck to “jackknife.”

How does Jack knifing happen?

When the trailer springs are over-greased. When travelling sideways across a slope. When trying to reduce speed sharply while travelling downhill. ...

What is meant by jack knifing?

Jackknifing refers to the folding of an articulated vehicle so that it resembles the acute angle of a folding pocket knife. If a vehicle towing a trailer skids, the trailer can push the towing vehicle from behind until it spins the vehicle around and faces backwards.