What causes the jackknife effect when driving with a trailer?

The options are not shown, since this is one of the 1,000 paid questions.
Buy all 1,000 questions now

Jackknife effect: “The car brakes more effectively than the trailer.” (Driving Licence Book, 19th Edition, page 173)

The car brakes effectively, but the trailer brakes poorly. This means that the trailer has to go somewhere (speed and force remains, as the trailer has not come to a full stop). This is called the jackknife effect, as the trailer will slide either to the right or the left and thereby fold in towards the car like the blade of a jackknife. The forces are so great that the car is also affected and will be pulled along – a very dangerous traffic hazard!

Körkortonline.se offers driving licence theory tests in English (free demo test), Swedish (free demo test) and Arabic (free demo test). This is an example of an explanation of a test question.

More examples of explanations:

Free demo – try 65 questions

Buy all 1,000 questions in English for car (category B)