When must you signal to change lanes?

When changing lanes, signaling must be done at least 100 meters (328 feet) before the maneuver. This requirement is in place to provide adequate notice to other drivers of your intention to change lanes, allowing them to react appropriately and maintain safety on the road. Signaling well in advance helps prevent misunderstandings and collisions, ensuring that all road users are aware of each other's actions.

The necessity to signal only when another vehicle is present or when turning does not align with safe driving practices and can lead to confusion on the road. Signaling is a proactive measure that should always be used whenever changing lanes, regardless of the presence of other vehicles.