Every road project comes with its own risks, and some of the biggest are the fixed structures built into the design. Barrier ends, bridge piers, sign supports, and even toll booths, while essential, they turn into serious hazards the moment a vehicle strikes them. The blunt ends in particular are dangerous and often lead to severe crashes if left unprotected. That’s where crash cushions step in.
Engineers build these barriers to stand in front of structures and absorb the impact before a vehicle reaches the concrete or metal behind them. In this guide, we’ll break down the types of crash cushions, how they work, and where they fit best into your projects.
What are crash cushions?
Crash cushions, also known as impact attenuators, belong to the family of crash barriers and serve as essential road safety equipment. Just like road barriers, they also absorb the kinetic energy during a collision. Their design and application are the two features that make them different from road barriers.
Crash cushions are placed at the ends of obstacles, including crash barriers. Their purpose is to lower the impact of the frontal collisions. They also prevent roll-overs and twists. They are MASH-rated and provide the required protection in different traffic environments.
Learn more about MASH ratings and their different levels in this article: MASH ratings explained
Types of crash cushions
We are discussing two different classifications of crash cushions.
Redirective vs non-redirective crash cushions
There are two types of crash cushions, classified by how they impact the vehicle during a collision.
Redirective crash cushions
As the name suggests, redirective crash cushions guide the vehicle back to its original path or toward a clear zone where it can control its speed without hitting any obstacle.
Non-redirective crash cushions
These crash cushions do not redirect the vehicle; rather, they stop the vehicle by absorbing its kinetic energy.
Sacrificial vs repairable crash cushions
This classification is based on how the barrier itself responds to the collision. It determines the usability of the barrier.
Sacrificial crash cushions
Manufacturers design sacrificial crash cushions for one-time use. After a collision, crews discard them because their deformation makes them unusable again. For example, sand barrels and water-filled crash cushions.
Repairable crash cushions
These crash cushions are designed for multiple uses. They also deform to absorb the impact. However, they can be brought back to their original form through specific techniques based on their design.
Repairable cushions are often preferred over sacrificial cushions due to their low maintenance cost and reusability.
Here’s an example of both of these classifications. Legend Hire’s Absorb M Treatment Crash Cushion is a non-directive crash cushion, while our Xpress Repair Cushion is redirective and repairable. When hit by a vehicle, its steel frame shrinks, absorbing the impact and slowing down the vehicle. You can stretch the steel frame again through a winch.
While the repairable crash cushions are considerably more expensive than sacrificial units, their repair and replacement costs are much less than those of sacrificial units, making them the smart choice in the long term.
How crash cushions work
Crash cushions work in a similar way to crash barriers. Their main task is to absorb the kinetic energy of the vehicle to either redirect it with significantly low speed or to stop it. This absorption results in the deformation of the crash cushions.
In frontal or head-on collisions, the crash cushion absorbs the impact and deforms. This results in stopping the vehicle safely in line and preventing roll-overs, twists, slips and hitting other vehicles or obstacles. In case of side collisions, they act as a road barrier, deflecting the car back to its original path or to a clear zone.
Learn more about impact absorption and crash barriers’ response to collisions in our deep dive on how crash barriers work to save lives.
Applications: Where are crash cushions used?
Footpaths, medians, pavements, and even crash barriers are a part of our road systems. However, their blunt ends can be dangerous in case of a head-on collision. The structures can crash into the car, causing disastrous results for the passengers. Instead of letting a vehicle crash directly into a solid structure, these cushions absorb the force or redirect the vehicle safely, reducing injuries and damage.
The following are the structures where crash cushions are used to shield the ends.
- Highway medians
- Exit and entrance ramps
- Bridge piers and abutments
- Toll plazas and gantries
- Work zones
- Roadside hazards
- Tunnel entrances
- Crash barrier ends
Crash cushions and road safety equipment for hire
At Legend Hire, we make road safety simple for our clients. Our range of road safety equipment, including crash cushions, barriers, anti-gawk panels and many other products, ensures our clients get the right product for their project requirements. Our team walks them through all the options and guides them on the safe, compliant and reliable solution.
Whether you need a quick setup for a work zone or a long-term solution that can be repaired and reused, we’ve got options that fit the job. Everything is MASH-rated and built for real-world conditions, so you can focus on getting the work done while we take care of the safety side. Need advice? Give us a call or explore our road safety equipment.