Which action is considered a major driver error that would likely lead to a fail during a test?

The action of turning sideways suddenly is categorized as a major driver error primarily because it poses a significant risk to both the driver and other road users. Sudden movements, especially those that are unpredictable, can lead to loss of vehicle control or an increased chance of collision, making it a critical safety concern during a driving test. Such erratic behavior demonstrates a lack of proper vehicle handling and awareness of one’s surroundings, which are essential elements of safe driving.

In a driving test context, maintaining smooth and controlled maneuvers is vital. While the other actions, such as speeding within a school zone, turning without signaling, and failing to yield, can also result in serious safety violations, the unpredictability of a sudden sideways turn amplifies potential dangers, making it a more severe error in the eyes of an evaluator. Therefore, demonstrating controlled and predictable driving is crucial for success during a driving test.