The correct answer is: Psychological extra widening depends on the speed of vehicle.
Psychological extra widening is the tendency for drivers to perceive a lane as narrower when they are driving faster. This is because drivers need to take into account the time it takes for their vehicle to stop, and they need to leave more space between themselves and the car in front of them when they are driving faster.
Mechanical extra widening is the actual widening of a lane that is required to accommodate the width of vehicles. This is typically done by adding shoulders to the road or by widening the lanes themselves.
The length of the wheelbase of a vehicle does not affect psychological extra widening. However, it does affect mechanical extra widening, as longer wheelbase vehicles require wider lanes.
I hope this explanation is helpful. Please let me know if you have any other questions.