When should hazard warning signals be activated?

Hazard warning signals should be activated when performing emergency vehicle maintenance on the road shoulder. This action alerts other drivers that your vehicle is stationary and possibly disabled, indicating that caution is necessary as they approach. Activating hazard lights enhances visibility and safety not only for the driver performing maintenance but also for approaching traffic, allowing them to adjust their speed or change lanes if needed to avoid potential accidents.

In the context of the other choices, activating hazard lights while driving over the speed limit does not communicate a clear warning to other drivers and is not a valid reason. Similarly, when parked legally, there is typically no need to signal to other drivers, as there is no immediate hazard present. Being in a hurry does not warrant the use of hazard signals, as this does not indicate a condition that requires other drivers to exercise caution. Therefore, using hazard warning signals specifically during emergency maintenance is the appropriate and safe action.