Abstract: A crash barrier that includes barrier sections that are overlappingly joined in assembly. Each section includes a concave center segment cojoined to upper and lower convex sections. Elongated longitudinally extended studs are punched out of one end of each section within the concave center segment. The studs are arranged to engage receiving slots in the other end of each section to facilitate assembly and alignment of the sections upon vertically disposed posts that are driven into the ground. A special machine for assembling and aligning the sections with the support posts is also disclosed.