What device can drivers use to alert others of potential danger on the road?

The horn is a common device used by drivers to alert others of potential danger on the road. When activated, it produces a loud sound that can quickly draw attention. This is especially important in situations where a driver needs to warn pedestrians, other vehicles, or cyclists about an imminent hazard, such as when another driver is about to make an unsafe maneuver or when pedestrians are in a crosswalk.

While hazard lights, headlights, and rearview mirrors serve different purposes, they do not function primarily as alerting devices in the same way the horn does. Hazard lights indicate that a vehicle is stopped or experiencing a problem, headlights improve visibility, and rearview mirrors help with spatial awareness and monitoring traffic surrounding the vehicle. However, none of these play a direct role in alerting others to imminent dangers on the road like the horn does.