What do the rectangular and circular signs on the expressway mean?

Rectangular signs: direction, tourist area and assistance.

Circular signs: prohibition, safety and explanation

Equilateral triangle: used for warning signs.

Circle: used to prohibit and indicate signs.

Inverted equilateral triangle: a forbidden sign for "slowing down and giving way".

Octagonal: used for "stopping and giving way" without signs.

Fork: Used as a warning sign of "Railway Crossing Fork Sign".

Square: used for guiding signs, some warning, prohibition and indication signs, tourist area signs, auxiliary signs, notice signs, etc.

Except for individual signs, the border color of the sign is consistent with the color of the logo graphic or text, and the lining color of the sign should be consistent with the background color of the sign except for the indication sign.