Smashing Barriers

Road safety barriers are often the last line of protection for motorway drivers. A basic necessity on the UK’s growing network of motorways and roads, the implementation and design of such systems was historically the full responsibility of the Highways Agency. Today, however, the government organisation works hand in hand with a number of road barrier manufacturers and industry associations to ensure such practises are fully optimised and that the organisation’s transition programme to concrete is upheld.

The Highways Agency, which is part of the UK’s Department for Transport and was first created in 1994, is primarily responsible for operating England’s strategic road network – consisting of most motorways and important A roads. It is along these major transport routes that the pressures of road safety management are most severe. In 2004 14,308 people were injured on UK motorways, of which 164 were killed and a further 1,137 suffered serious injuries, such as loss of limbs, paralysis and brain damage.

Within the Highways Agency, the Vehicle Restraint team is focused on developing the role of safety barriers, which is fast becoming a more diversified field due to the increasing array of products now on the market. The team’s senior technical advisor, Daniel Ruth, is quick to highlight the evolving role of manufacturers within the road safety barrier market.

“There is certainly more choice now in terms of safety barriers. Manufacturers are becoming increasingly responsible for the design and development of the products,” says Ruth.

“There are now many types of road safety barrier varying in design, size, performance level and material. Some are concrete, others are steel, aluminium or plastic and some are a combination of concrete and metal. The barriers are primarily implemented on roads and bridges, and a list of accepted vehicle restraint systems is found on the Highways Agency website.”

Concrete approach

In January 2005 the Highways Agency made the mandatory transition from steel to concrete barrier reserves on motorways with high volumes. Behind this move was the realisation that concrete barriers require less maintenance. Even after a vehicle impact, concrete barriers are less likely to require repair and therefore minimise the dangers surrounding road repair works and ensure traffic flows are less disrupted.

“Concrete and steel barriers reduce a lot of incidents at crossovers. Both materials will prevent accidents as long as they are of the right containment level, which is generally H1H2,” says Ruth.

“However, the advantage of using concrete in a central reserve is that it is maintenance free, which means if a steel barrier was hit then we would have to send in a roadworks team to physically repair the barrier, while with concrete barriers, after an initial clear up has been completed, the roads are free and you are able to move the traffic forward.”

To date, the Highways Agency has begun the transition from steel to concrete on roads with an average daily traffic flow of 25,000 each way. Encompassing most major motorways, the hectic M25 and M1 were the first to adopt the more resilient concrete barriers. Since then, the scheme has generally been adopted on motorways experiencing widening programmes.

“I would say the concrete barriers have lived up to their expectations,” says Ruth. “You have to analyse the costs and in terms of reducing crossover accidents. Our research found that over a two-year period on the M25, no maintenance was required on any of the concrete barriers on those particular motorways.”

European Union boundaries

All road safety barriers on UK roads are tested in accordance of the European Standard EN 1317. Within this standard, barriers must pass specific performance requirements, facing stringent testing against vehicle weights ranging from 1.5t up to 30t.

Testing also covers aspects such as the speed of the vehicle and the angle of the vehicle’s impact. While such tests were once the responsibility of the Highways Agency, today the impetus lies with the manufacturers which send new systems out to be examined at independent approval bodies.

“The responsibility now lies with manufacturers to develop road safety barrier systems. There is a lot more involved in the process then when it was the Highways Agency’s responsibility, through developments such as computer modelling,” says Ruth.

“The manufacturers are always looking at ways to improve on the performance of the barriers they have already got. The development of the systems now really lies with them.”

A barrier collision course

Hill and Smith has been manufacturing steel safety barriers since the 1970s and since then it has developed a close working relationship with the Highways Agency. Yet while the Wolverhampton-based company is quick to identify the government organisation as its primary end user, it also has to work closely with installation companies, such as Balmer Lindley Group, and independent certification bodies, such as the Motor Industry Research Association (MIRA).

Hill and Smith’s technical sales engineer Matt Harriman is quick to acknowledge the change in the road safety barrier market since the Highways Agency’s decision to outsource the design and testing of the systems. “MIRA is now the approved body and test-house for road safety barriers in the UK. As this process is now done privately, it ensures no manufacturer is favoured more than others,” he says.

“However, while this has led to an increase in competition between manufacturers in Europe, we have been quite fortunate in the UK, where there are only two manufacturers – Hill and Smith and Corus. When the decision was made to transfer testing to MIRA, only the largest companies survived as the testing process itself became more expensive.”

Hill and Smith has been involved with ongoing testing at MIRA’s headquarters in Nuneaton, Midlands, for the last four years. The site offers full-scale crash tests where a 100m strip of Hill and Smith’s barriers are typically tested at a time.

“The barrier is installed at the side of a road and the car is winched towards it at 70mph. The winch is the released before the fence so the car is in effect in free motion,” says Harriman.

“The car then has to hit the barrier in a controlled manner, it cannot be flipped over or stop straight. Depending upon how much it deflects upon impact, the barrier then receives certification.”

While concrete barriers have been used in mainland Europe for several years now, their implementation is not as widespread throughout the UK. The next few years therefore remains pivotal to the programme and to the research of company’s such as Hill and Smith.