I was asked a question registering in an agency and I am not sure what was the proper answer
Jack Knifing is more likely to occur when driving:
- Flat bed lorry
- Ladden lorry
- Unladden lorry
- High sided lorry
scyzor:
I was asked a question registering in an agency and I am not sure what was the proper answerJack Knifing is more likely to occur when driving:
- Flat bed lorry
- Ladden lorry
- Unladden lorry
- High sided lorry
Unladen, because there’s insufficient weight on the trailer to hold it steady, but it’s possible that it will jack knife loader in the snow etc.
Sam Millar:
scyzor:
I was asked a question registering in an agency and I am not sure what was the proper answerJack Knifing is more likely to occur when driving:
- Flat bed lorry
- Ladden lorry
- Unladden lorry
- High sided lorry
Unladen, because there’s insufficient weight on the trailer to hold it steady, but it’s possible that it will jack knife loader in the snow etc.
A laden vehicle is more likely to jack knife as that what contributes to jack knifing
Jack Knifing occurs when the tractor unit starts to slide sideways and the weight of the trailer pushes the rear of the tractor round further until they are no longer facing the same direction. In times gone by before all airline couplings were automatic there used to be air taps on each air line. If a driver forgot to open the tap on the service line (yellow) effectively he would be driving with no trailer brakes at all. With no trailer brakes the entire vehicle depended soley on the tractor brakes to stop.
There used to be a blue airline which operated a secondary braking system. This was operated by a lever in the cab and applied only the trailer brakes. In theory this system would have prevented jack knifing as the trailer was pulling back the unit. Unfortunately it led to problems through overuse as the trailer brakes would get extremely hot and brake fade occured where the drums became so hot they expanded away from the shoes reducing braking effectiveness. Once this occured when the driver operated the footbrake, the unit would attempt to stop but not so the trailer.
The answer to the OP question is therefore 2. Laden lorry
The DSA definition is that an UNLADEN VEHICLE is more likely to jack knife - the reasoning is that the trailer being lighter looses grip and the skids around. 
The correct anwser would have been Unladen mate
- I’ll bet the original poster is still unsure what the correct answer is !!!
I find it worrying in the extreme that people come on to this forum and give out duff information which new drivers will then take on at face value.
Perhaps these guys would be better off being employed as DCPC tutors, … In fact some of them probably already are. 
Deesider:
:lol:
- I’ll bet the original poster is still unsure what the correct answer is !!!
Perhaps these guys would be better off being employed as DCPC tutors, … In fact some of them probably already are.
+1
Think about it logically. The weight of the trailer pushes the rear of the tractor unit and continues to surge forwards until friction or object stops it in its path
chevmac:
The DSA definition is that an UNLADEN VEHICLE is more likely to jack knife - the reasoning is that the trailer being lighter looses grip and the skids around.
Do you mean the tractor unit loses grip and is pushed round?
Wheel Nut:
chevmac:
The DSA definition is that an UNLADEN VEHICLE is more likely to jack knife - the reasoning is that the trailer being lighter looses grip and the skids around.Do you mean the tractor unit loses grip and is pushed round?
fair comment - reading it back I have probably better discribed Trailer Swing 
I think the fact that the tractor unit is pushed around is more likely to happen with a heavy trailer therefore not unladen - but the answer to the op is correct with an Unladen trailer
John