Ontario MTO Truck Knowledge Practice Test

Over-braking in certain situations can indeed lead to skidding or jackknifing. When a driver applies the brakes too forcefully or abruptly, especially in slippery conditions or when the vehicle is heavily loaded, it can cause the wheels to lock up. This loss of traction may result in the vehicle sliding uncontrollably, which is known as skidding.

Additionally, in the case of combination vehicles, excessive braking can lead to a jackknife situation where the trailer swings out sideways in relation to the tractor unit. This can create a highly dangerous scenario, potentially leading to accidents as the vehicle becomes difficult to control.

The other options, like increased fuel efficiency or better traction, do not follow from the action of over-braking. Similarly, while improved handling is generally beneficial, excessive braking tends to compromise rather than enhance a driver's ability to steer and control the vehicle effectively.