The guardrail is mainly to follow the AASHTO M180, GB-T 31439.1-2015 and EN1317 standard.
The material for that are mainly the Q235B (S235Jr the yield strength is more than 235Mpa) and Q345B (S355Jr the yield strength is more than the 345Mpa).
For the thickness of the guardrail mainly through the 2.67mm to 4.0mm.
The surface treatment is hot dipped galvanized, to follow the AASHTO M232 and the equal standard such as AASHTO M111, EN1461 etc.
The guardrail designed for divide the road into different part, and lower the damage while the accident accrued.