A highway guardrail is the barrier that helps slow and stop vehicles that are careening to the side and redirects vehicles back onto the road. Thorough research has been put into the guardrails’ designs to ensure that they fulfill their functions as effectively as they can. Yet while they are so vital in making countless roads safer for drivers, they still retain an admirable simplicity that keeps them from becoming a distraction. Below, we describe each of the highway guardrail parts and what they do.


The actual rail parts of the highway guardrail, sometimes also referred to as the panels, are the pieces that directly touch oncoming automobiles. They may come in different designs and materials based on what an area requires or wants. To illustrate, a road that many trucks and other larger vehicles use may have three-beam rails. These are wider than the typical W-beam and can stop those vehicles with a higher center of gravity without causing them to flip over. While most rails are made of steel, some are comprised of wood to look more attractive.

Posts and Blocks

The guardrail’s posts hold it up. Posts may also be made of metal or wood and are intended to give way to a car that crashes into them while slowing it down. Similar to how the front of a vehicle is made to crumple to reduce the force of impact on the people inside, so too do the posts move back while still remaining sturdy enough to make a positive difference.

The blocks are located between the posts and the rails. By creating some space between those two components, the blocks prevent the vehicle and rail from snagging on each other. They also maintain the position of the rail toward the top of the posts so that vehicles don’t move up and over the guardrail.


If cars were able to hit the guardrails head on at each rail’s beginning, the rails could spear them, but the terminal—the component of highway guardrails that caps off its ends—prevents this from happening. Terminals are rounded so that the car and the guardrail slide against one another, with the guardrail bending back as necessary. The impact is thus absorbed safely.

If you are in need of highway guardrail installation, call Durham Fence & Guardrail. We have completed guardrail projects for government agencies from the local to federal levels. Whether you need a guardrail for a highway, parking lot, or retaining wall, you can trust us to get the job done right. Contact us today to learn more about the parts of a highway guardrail or anything else we have to offer.