How w-beam guardrail is made and installed

Roadway guardrails are normal in our daily life. We can see them in the express way, city road and sometimes even countryside. However, not everybody have the idea have guardrail is made.
The picture below shows the procedure of guardrail making.

After a road is built, especially the highway, we need try our best to ensure when some cars become errant, they can get protection to the biggest extent, guardrail or crash barrier is needed. But how to install guardrail?

I believe you all get a clear idea about how the guardrail is made and installed. If you need to know more about road safety facilities, you can Google Wuhan Dachu Traffic Facilities to know more.