The Physics Behind Crash Barriers

Buildings & Storage Barriers

We’ve all seen crash barriers before – they’re found in warehouses, on industrial estates, in multi-storey car parks and on roads. But how much do you actually know about how these barriers work?

Obviously, barriers are put in place to improve safety management. In areas where there is potential for vehicles and/or pedestrians to crash or collide, some kind of barrier is usually implemented. This might be an Armco barrier, a concrete barrier, a temporary barrier, a flexible barrier or a temporary barrier solution, and all of these will work in slightly different ways.

In this article, we’re taking a look at what crash barriers are, how they work, where they come from, and why they’re so important when it comes to the topics of road traffic safety, pedestrian safety and driver safety.

Safety Science & the Physics of a Collision

One of the most important jobs of crash barriers is to stop vehicles from moving as quickly and safely as possible. This is a delicate balancing act, due to the impact of g-force on vehicle drivers and passengers. When you’re driving, you and your vehicle possess kinetic energy and when you stop suddenly, this energy has nowhere to go! This is when you’ll experience g-force.

If you’ve ever been in a car collision, had to do an emergency stop, or even just had to slam the brakes on quickly, you’ll have experienced first-hand the effect that G-force can have on passengers in a vehicle. That feeling of “pulled” or jolted forward as the vehicle around you stops can actually have a huge impact on the severity of a collision or crash in any vehicle. Learn more about the physics here.

There are a few things that impact the physics behind g-force, and how strong or severe it is in a collision. Things to consider when working out the g-force of a collision (and therefore how likely it is to be a severe or even a fatal crash) include:

  • The vehicle speed – How likely are vehicles to be travelling at high speed in this context? The faster a vehicle is travelling, the more speed it has and the higher the level of g-force stopping suddenly can generate.
  • Are drivers/passengers wearing a seat belt? – Seatbelts are a legal requirement, and for good reason. The effects of g-force on individuals in a rapidly stopping vehicle can actually throw you from your seat, while a seatbelt will lock to keep you much safer.
  • The vehicle type – you are more likely to survive a car crash if you’re in bigger car, or larger vehicle, due to the physics behind collisions. However, larger vehicles can obviously cause more damage to buildings and pedestrians around them as well.
  • The obstacle type – Now this is where crash barriers come in. Collisions are likely to be much more serious when a vehicle hits a solid object like a tree or building, compared to a hedgerow or barrier. This is because the impact of the g-force is heightened when colliding with an immovable object. Crash barriers and Armco barriers have all been designed with this principle in mind.

So, How Do Crash Barriers Work?

At their core, road barriers exist to prevent severe injuries in the result of road crashes, and they do this by stopping a vehicle as safely as possible. After all, a pickup truck, delivery van or even just a car can’t do as much damage if it isn’t moving!

However, there are actually plenty more safety performance functions to consider when creating barriers and when implementing them too. These many parameters have been honed over generations of safety improvements, and thousands of safety decisions have been made over time to ensure that modern-day crash barriers meet modern-day safety evaluations and safety studies!

In addition to protecting people and property, traffic barriers protect vehicles and vehicle users, and need to do this effectively on all sides. That’s a high bar to set for safety products. So, how do traffic barriers reduce severe injuries and accidents under such circumstances, where vehicles may be travelling at high speeds and pedestrians and site workers may be at risk for injury?

Barriers are designed to deform

While you might think that a barrier should be designed to be as strong and rigid as possible in order to stop any collisions straight away, you’d actually be causing more harm than good! Crash barriers, including Armco barriers are actually designed to deform to an extent. When impacted by a vehicle, these barriers will actually bend and crumple before they snap! This is for a few reasons:

  • To reduce g-force by preventing the vehicle from coming to a hard stop instantly on collision.
  • To spread the energy produced across different sections of barrier, rather than a single impact point (this reduces the physical strain on the barrier).
  • To prevent sharp metal sections snapping or flying off, which can be a significant hazard.

Of course, every situation has multiple variables: the force that a car exerts on a crash barrier varies depending on the kind of vehicle, its weight, and how fast the vehicle is moving. Crash barriers still need to be able to withstand significant forces in order to have these safety effects, which is why they’re made from galvanised steel and why they’re fixed to the ground using bolt-down or dig-in posts.

Armco barriers are also designed in sections so that in the case of a collision, only a small section of your barrier needs to be replaced, rather than the whole barrier or fence. By only having to purchase a few replacement beams and posts, you can save on costs while still feeling confident that you’re building the most effective safety barrier you can. 

Crash barriers are carefully placed

Guardrails or crash barriers are used to prevent vehicles from exiting a road when the off-road environment would be more dangerous than crashing into a barrier. However, there is a possibility that forgoing the fence is actually a safer option if there is just empty land or fields beyond the proposed location of the barrier.

With that said, it is not uncommon for there to be steep drops, ditches, trees, or other obstacles to exist around industrial sites that would make it extremely dangerous for drivers to leave the road. Whenever possible, engineers will weigh the advantages and disadvantages of constructing barriers or guardrails to offer the safest route for drivers.

As well as reducing the force of impact, barriers provide a protective obstacle to ensure any vehicle does not leave the road and fall into further hazards, including water, embankments, steep slopes or trees.

Crash barriers are made to be fit-for-purpose

Although we naturally assume that something which is strong offers the best type of protection, having a heavy-weight, rigid barrier is not actually the right type of roadside protection for vehicles. Ensuring crash barriers and Armco barriers are fit for purpose actually means implementing relatively lightweight barriers that are designed to readily deform in crash conditions and keep vehicle users and roadside pedestrians and workers safer. Of course, they still need to be strong enough to stop vehicles and large equipment, but they must also have a level of flexibility.

History of Crash Resistance Barriers

In the early-mid 20th century, cars were designed with a solid chassis, which meant if they crashed, there was no “crumpling”, and they were designed to hold in the case of a collision. Unfortunately, this actually ended up being incredibly unsafe, as in the even of a collision, passengers were at more risk from g-forces, being thrown from the car, or the car breaking in unsafe ways. In modern cars, the front is designed to feature a “crumple zone”. Most vehicles since the 1990s have had this feature, which first appeared in Volvo cars, and was very quickly adopted by the rest of the automotive industry. This crumple zone allows the car to bend and break in the safest way possible for the passengers, while also reducing g-forces.

Just like the vehicles on our roads, in our car parks and in our warehouses, crash barriers (including Armco barriers) have also developed to be safer over time – Learn more. Most guardrails, until around 1980, sloped down at the ends and were buried into the ground, but today, a flat metal face at the end of a barrier more evenly distributes the impact on the car, reducing risk in the even of a collision. The combination of these changes and improvements in automobile safety features have saved many lives over the years.

Armco Crash Barriers

Armco crash barriers are a specific type of barrier that is easily identified by its corrugated appearance and easy-to-assemble structure. The purpose is to protect the public where a significant risk of harm has been identified, and where allowing vehicles to continue their route would lead to far less serious consequences than the collision with a barrier. Armco barriers are not only implemented to stop moving vehicles, they are also designed to minimise collision impacts.

Materials Used in Armco Barriers

The barriers are made from galvanised steel which feels very rigid and strong to us, but it actually has an element of flexibility – this is due to its unique corrugated shape. Steel is a very strong, hard material, but it does actually have properties that allow it to be flexible. This means that in the event of a collision, the energy produced is spread across a wide area, not just a small section, and so the force of the impact is reduced.

 At Armco Direct, all of our metal barrier beams, posts and fixings are made from BS EN 1461 galvanised steel.

The Design of an Armco Barrier

The design of Armco barriers also ensures that on impact, any vehicles that collide with the barrier are encouraged along the barrier line. This also prevents vehicles from flipping or turning and ensures they stop quickly and efficiently. As well as preventing additional damage to buildings, vehicles and drivers, this also helps to keep pedestrians and other path users safe, as vehicles are brought to a more controlled stop.

Additional Guardrails, Handrails and Barriers

As well as the many safety considerations that need to be taken into account, barriers often also have a dual purpose, so they need to be practical too. Many barriers will also need handrails to help improve accessibility and make your barriers useful in multiple contexts!

To find out more about Armco barriers and crash barriers, or to order Armco barriers for your site, please don’t hesitate to get in touch with the team here at Armco Direct. Alternatively, take a look at our calculator to work out what your barrier needs are. Our team will be in touch to offer you a comprehensive free quote within 24 hours based on your needs, and we can offer delivery across the UK in under 48 hours.

So what are you waiting for? Get started with Armco Direct today.