When is a driver required to use their turn signal?

A driver is required to use their turn signal when changing lanes or making turns because the primary purpose of turn signals is to communicate intentions to other road users. By signaling, a driver is providing important information that helps prevent accidents and maintain safe driving practices. This communication is critical not only for other vehicles but also for pedestrians and cyclists, allowing everyone to anticipate and react appropriately to a driver's actions.

Using turn signals during lane changes or turns enhances safety on the road by ensuring that the movements of the vehicle are predictable. This is particularly important in high-traffic areas where other drivers may not be aware of a driver's next move. Drivers must signal well in advance of making the maneuver to give others ample time to notice and respond.

The other options do not accurately reflect the requirements for using turn signals: using them only at night would not provide the necessary communication during the day; arriving at a stop sign pertains more to stopping than signaling; and following another vehicle does not inherently require signaling unless the driver intends to change lanes or turn.