The main purpose of a Highway barrier along the highway is to form a safety barrier to help protect a motorist who has drifted off the road.Utility poles, bridge piers and retaining walls are other obstacles. In these cases, striking a guardrail would be greatly preferable to striking the obstacles, so guardrails are usually installed.They lessen the severity of a potential crash and make the roads safer.The guardrail can act in a myriad of ways from deflecting a vehicle back onto the road, slowing it down or stopping it, or in some cases just slowing it down enough and allowing it to proceed past the guardrail.