When must a driver use turn signals?

A driver must use turn signals when changing lanes or turning because this practice is essential for ensuring the safety of all road users. Turn signals communicate a driver's intentions to others on the road, including pedestrians, cyclists, and other vehicles, allowing them to anticipate movements and react accordingly. Utilizing turn signals helps prevent accidents and promotes smoother traffic flow.

In contrast, using turn signals solely when parking, only when driving in reverse, or only on highways does not encompass the full range of situations where signaling is crucial. For instance, signaling while changing lanes or turning can occur in various areas, including city streets, residential neighborhoods, and highways, reinforcing the importance of consistent use of turn signals across all driving situations.