Georgia Commercial Driver License Practice Test

Which of the following is typically NOT a cause of jackknifing when pulling a trailer?

1. Loss of braking power

2. Reduced tire traction

3. Improper weight distribution

4. Engine overheating

The correct answer is: Engine overheating

Jackknifing occurs when a trailer swings out from behind a towing vehicle and forms an acute angle with it, which can happen due to several factors. The reason why engine overheating is typically not a cause of jackknifing relates to the mechanics of how a trailer is towed and how jackknifing occurs. Engine overheating affects the performance of the vehicle but is not directly responsible for the loss of control that leads to jackknifing. Loss of braking power can lead to jackknifing because if the towing vehicle cannot stop effectively, it can lead to the trailer catching up to the tow vehicle, causing it to pivot sharply. Similarly, reduced tire traction impacts how well the vehicle and trailer can maintain control on the road, especially in slippery conditions. Improper weight distribution affects how the load is centered and can increase the likelihood of the trailer swaying or tipping, which may result in a jackknife. In contrast, while engine overheating can cause some performance issues, it does not inherently create the conditions for jackknifing. It is more associated with the engine's power and efficiency rather than the dynamics of trailer towing.