How can a driver test the horn during a pre-trip inspection?

To assess the functionality of the horn during a pre-trip inspection, the driver should actively press the horn to confirm that it emits sound. This method ensures that the horn is working properly and can be relied upon to alert others on the road if necessary. It is essential for a driver to check the horn during the inspection because a functioning horn is a critical safety feature that plays a significant role in communication and hazard awareness.

Relying solely on listening for a faint sound may not provide a definitive confirmation of the horn’s operational status, as it could be too quiet or malfunctioning. Visually checking the horn does not guarantee that it will sound in practice. Using an external speaker to test sound is not a standard or effective method for ensuring the horn's functionality, as it deviates from the intended design of the vehicle’s alarm system. Thus, physically pressing the horn is the best practice for ensuring it is in working order.