Speed limit signs mainly include maximum speed limit signs, minimum speed limit signs, end-of-speed-limit signs, road surface speed limit markings, and suggested speed signs.
Maximum speed limit signs are white with a red circle and black lettering; minimum speed limit signs are blue with a white circle and white lettering; end-of-speed-limit signs are white with a black circle and black lettering with a diagonal slash; in road surface speed limit markings, yellow numbers indicate the maximum speed, and white numbers indicate the minimum speed, which can be summarized as "yellow for maximum, white for minimum."
The placement of speed limit signs needs to comprehensively consider various factors such as highway function, technical grade, roadside development level, route geometry, operating speed, traffic accident data (at least the most recent 12 months), and environment. The difference in speed limits between adjacent road sections should not exceed 20 km/h. For special speed-limited road sections such as sharp curves and areas with insufficient visibility, in addition to setting speed limit signs, comprehensive measures (such as active guidance and forced deceleration) are required, and minimum length requirements must be met.
