Washers are used to secure secure the bolts to the guardrail. Highway guardrail bolts and nuts are mainly used between guardrail and spacer or between spacer and post.They play a fixed role when the vehicle collides with it, the corrugated steel guardrail board has good crash worthiness and energy absorption, and it is not easy to be destroyed, and at the same time it can protect the vehicle and the passengers. When the road maintenance or other reasons need to be connected, the groups of guardrail columns at the opening can be easily removed and removed to open the passage for the vehicle to pass.