Tunnel Warning Sign - Road Safety Symbol Explained #3761696 (License: Personal Use)

The image shows a regulatory road sign in the shape of a red-bordered equilateral triangle with a white background, featuring a black silhouette of a stone-arched tunnel entrance. This sign is used internationally (especially in Europe) to warn motorists of an imminent tunnel, prompting them to adjust speed, turn on headlights, and be alert for sudden changes in lighting and air quality. It complies with Vienna Convention on Road Signs and Signals standards.

Used on highways and rural roads before tunnel entrances; supports driver awareness and accident prevention. Matches user intent for traffic sign identification, driving test preparation, or road safety education.