Time to rethink road barriers

Roller barriers placed at the underpass along Jalan Lapangan Terbang Subang in Petaling Jaya to protect motorists during accidents. — GLENN GUAN/The Star

AUTHORITIES must rethink conventional metal guardrails to make Malaysian roads safer.

One technology deserving closer attention is the safety roller barrier, a road restraint system designed not only to contain out-of-control vehicles but also to absorb and redirect crash energy.

One example of the roller barrier is a 100m stretch of underpass along Jalan Lapangan Terbang Subang in Petaling Jaya, Selangor, heading towards the Federal Highway.

It was selected as a test site in December 2016, following concerns over the high number of accidents occurring around a sharp bend.

A friend’s car recently crashed into the Jalan Lapangan Terbang Subang roller barrier, which immediately redirected the vehicle safely back onto the road.

She was unhurt.

Unlike traditional guardrails, the roller system consists of sturdy steel supports fitted with brightly coloured, spinning plastic cylinders.

When a vehicle strikes the barrier, the rollers rotate on impact, converting some of the vehicle’s kinetic energy into rotational energy.

Instead of bringing a vehicle to an abrupt stop or allowing it to rebound unpredictably, the system is designed to absorb and redirect the force of the collision while guiding the vehicle along the barrier.

Ideally, this helps keep the vehicle within the roadway and reduces the likelihood of it being thrown into another lane, overturning or veering off the road altogether.

The question now is whether Malaysia should move beyond isolated trials and examine the wider use of such systems, particularly at locations identified as high-risk.

The bus crash in Gerik, Perak, in June 2025, which claimed the lives of 15 people, raised renewed concerns after a section of the metal guardrail reportedly penetrated the bus’ interior.

A guardrail is intended to protect road users, but its safety performance depends on how it acts during a collision.

A barrier that fails to contain a vehicle safely or -- in the worst circumstances -- becomes a hazard, raises questions about whether existing roadside protection measures are adequate for every type of vehicle and crash scenario.

Conventional guardrails still remain an important element of road safety infrastructure when properly designed, installed and maintained.

But road engineering must evolve with the risks brought about by increasingly large buses, heavy vehicles and higher traffic volumes.

Therefore, independent and evidence-based assessment comparing conventional guardrails with roller barriers and other modern vehicle restraint systems should be undertaken.

The assessment should examine crash severity, passenger protection, maintenance requirements, and performance in different weather conditions.

It has been almost a decade since the roller barrier at Jalan Lapangan Terbang Subang was installed. 

It is time to have one placed at the sharp bend of the slip road from the Federal Highway to Subang Jaya.

It is a way forward for road safety standards at the Subang Jaya “black spot”.

If evidence shows that roller barriers can reduce injuries and fatalities at high-risk locations, authorities should not hesitate to use it more widely.

Infrastructure designed decades ago along the Federal Highway should be continually reassessed against today’s traffic conditions and safety expectations.

When a driver loses control, the road should provide a second chance, not create another danger.

It is time to ask whether roadside barriers are doing enough to protect people.