Joke Collection Website - Bulletin headlines - What are the yellow and black signs on both sides of the expressway tunnel?

What are the yellow and black signs on both sides of the expressway tunnel?

Yellow and black elevation marks:

The elevation sign is a sign to remind drivers that there are structures higher than the road surface in or near the roadway to prevent collision.

Elevation marks can be set on the end faces or side walls of piers of overpass bridges and aqueducts. , as well as on the walls of tunnels and crosswalk safety islands.

What is the color of the elevation mark? Yellow and black? Inclined lines, the inclination angle is 45, and the line width and interval are 15cm. When setting, the downward inclined side should face the roadway.