The Application of Roller Barriers in Highway Safety

Roller Barrier is a road safety protection system that attempts to keep vehicles in their lane and prevent them from colliding with other vehicles. Conventional w beam guardrails can reduce accidents, but when a vehicle collides with a barrier, it can cause significant damage to vehicles and even result in injuries or fatalities. For this reason, the Korean company designed the " Roller Barrier System", which converts impact energy into rotational energy. The Roller Barriers are barriers fitted with rollers, consisting of a number of round EVA barrels (almost like tyres), connected by round steel posts. When a vehicle collides with a roller, it creates rolling friction and the rollers on the guardrail begin to roll when struck by the vehicle, preventing the vehicle from stopping suddenly or overturning, thus reducing the severity of the accident. It has proven to be more effective when used on horizontal bends where most accidents occur. Crash tests were conducted on three different vehicles, and the results show that the roller barriers meet the crash test standards for small cars, large cars, and passenger cars.

1. The traditional highway beam guardrail

Traditional highway w-beam and thrie-beam guardrails are safety facilities that attempt to keep vehicles in their lanes and prevent them from colliding with other vehicles. They are installed on both sides of the road, especially on curves, and these collision avoidance systems are made of steel, concrete, or even cable. These guardrails can be used as roadside guardrails, intermediate guardrails, bridge side guardrails, or work area guardrails, which are rigid and have little flexibility. 

2. The new roller barriers

South Korea was the first to study the new roller barriers, installed in curved road sections, within a year the accident reduced by more than 50%, which includes flexible characteristics and semi-rigid characteristics. They are different in principle from other types of guardrails, and polyurethane has become the material of choice for many of today's performance-driven applications because it has physical and mechanical properties that are unrivaled by other materials. In October 2016, the Malaysian government decided to use roller barriers to reduce accidents and improve safety. The concept of a roller barrier is a continuous post connected to a polyurethane barrel. The roller can rotate when it encounters a vehicle. It is made of special chemical compounds, such as hard rubber, that absorb the impact of vehicles. In concrete or waveform beam guardrails, the goal is to save human life, but the vehicle is the worst situation.

3. Working principle

Traditional guardrail systems, including concrete and waveform steel highway guardrails, attempt to absorb as much impact energy as possible from the impact of a collision, thereby breaking the momentum of the colliding vehicle. However, as we have seen from the number of fatal accidents on highways, such systems have proven to be substandard. Instead, roller barriers both absorb impact energy and convert it into rotational energy, helping to keep the vehicle on track and preventing it from tipping over. As can be seen from the diagram, when a vehicle deviates from its actual path and hits an obstacle laterally at any angle, the roller will rotate with the impact, converting the impact energy into rotational energy, rotational energy not only helps to reduce the impact of a collision, but also contributes to the safety of the highway using the roller barrier system, which is both flexible and semi-rigid in terms of barrier stiffness. The rollers are made of EVA with excellent shock absorption capacity and have a cushioning frame (height, width, and depth) and dense support posts. The roller has a light barrier for good visibility. EVA has better flexibility and tensile capacity than other polythene resins and has almost the same properties as rubber. In fact, it is lighter than rubber and more flexible than polyurethane.