When is it acceptable to change lanes without signaling?

Changing lanes without signaling is never acceptable because signaling is a fundamental rule of safe driving that contributes to road safety. When a driver uses their turn signal, they communicate their intent to other road users, allowing for better awareness and coordination among vehicles. This action is crucial in preventing accidents, as it helps others anticipate the movements of a vehicle.

In situations such as heavy traffic, if the lane is clear, or at intersections, the importance of signaling remains the same. Failing to signal in these scenarios can lead to misunderstandings, confusion, or even collisions, as other drivers may not expect a lane change to occur. Therefore, the correct answer emphasizes the necessity of signaling at all times when changing lanes to ensure the safety of everyone on the road.