The process of steel road barrier involves several steps. Here is an overview of the general process:

1. Design: The first step in the production of metal guardrails is to design the guardrails. Designers use computer-aided design (CAD) software to create designs.

2. Material Selection: Once the design is complete, the next step is to select the appropriate material for the obstacle. Common materials include steel, aluminum and iron.

3. Cutting: After selecting the materials, the next step is to cut them into the desired size and shape. This can be done using various cutting tools such as water jet, laser and plasma cutters.

4. Forming: After the material is cut, it is formed into the desired shape and size through various processes such as bending, rolling, and stamping.

5. Welding: After the parts are formed, they are welded together to form the finished barrier. Welding is done using various techniques, including arc welding and gas welding.

6. Finishing: After the obstacle is welded, it goes through the finishing process. This may include sandblasting, powder coating or painting to protect the metal from the elements and give it a decorative finish.

7. Quality Control: Before being shipped, metal fences go through a quality control process to ensure that they meet the required standards and are free from defects.

Overall, the process of manufacturing a metal barrier is a complex process involving many different steps that requires skilled workers with specialized knowledge and equipment.