Which of the following actions in traffic require a hand signal or a mechanical signal?

The requirement for using a hand signal or a mechanical signal applies to all the actions listed: slowing or stopping, making right turns, and making left turns. Each of these actions ensures that other road users, including pedestrians and cyclists, are aware of your intentions on the road.

When you slow down or stop, using a signal alerts drivers behind you that you are reducing speed or coming to a halt, preventing potential rear-end collisions. For right and left turns, signaling in advance is crucial for the safety of all road users, as it informs them of your planned maneuver, allowing them to adjust their actions accordingly.

Therefore, the correct answer encompasses all these situations as they are fundamental to safe driving practices and are legally required in many places, including Newfoundland and Labrador. Ensuring that you signal when performing these actions promotes better communication on the road and contributes to overall traffic safety.