safety Peter Simpson / Rex Features BARRIERS tonnes, they’ve proved resilient in withstanding an impact The Highways Agency is changing barriers from heavier trucks. “Of the five major HGV hits on motorway concrete barriers we’re aware of in the past five-and-a-half years, there’ve been no reported crossover accidents,” says Jones. Yet he describes the current rate of replacement as disappointing, adding: “Despite their recognised benefits, they’ve only been installed on some 10% of the motorway. The replacement programme of obsolete steel barriers with robust concrete installation needs to be accelerated. I think it’s important for CM readers because the [concrete] barriers have prevented crossovers, restraining well above their design. They’ve been holding 44-tonne trucks.”

Broadening the scope While any changeover will inevitably be dictated by the rate at which the current steel stock ages, Jones wants the HA to broaden the scope of its replacement programme. “The other thing we’d like is that this current policy only applies to The great barrier relief motorways – we’d like it extending to all trunk , many

Image: Rex Features Image: Rex of which are carrying very high volumes of .” Jones is also concerned as to what effect any possible budget cuts Since 2006 the Highways Agency has maintenance teams are exposed to less danger while might have on the HA’s barrier strategy. making repairs. Naturally, any reduction in repair time also The replacement of metal N2 barriers with H2 Britpave been cementing a plan to prevent HGV cuts consequent traffic congestion and delays. Concrete Step Barriers on English motorways is a work in Two types of concrete barrier are used on English motor- progress, which will last many years, especially as some of ‘middle-of-the ’ motorway accidents ways and selected A-roads. The most prevalent, adopted by the current metal stock will have been either new, or nearly the HA in 2006, is the Dutch Step. The 900mm-high new, in 2006 when the HA made its decision on concrete Words: Brian Weatherley vertical barrier features a distinctive, stepped-base profile. ▼ Concrete Step Barrier replacements. It will be closer to 2030 before those metal The other type, found on the M25, consists of two flat-face with deep base barriers are approaching the end of their working life. You don’t need to be a risk management guru concrete walls with an aggregate ‘in-fill’. The HA says: “There is no programme of replacement to see why motorways are the safest roads in Britain. When Five years on, the pace of replacing steel for motorway steel barriers, which have a service life of 20 all the traffic is travelling the same way, on the same with concrete might surprise some. Of the years. Agency policy is that high-containment rigid concrete carriageway, separated by a barrier from the opposite 1,823 miles of motorways in England (the barriers replace metal barriers when they reach the end of carriageway, the odds of a collision are far lower than on a HA is not responsible for motorways in their usable life and where motorways are being construct- typical two-, two-way road. And although the risk of a Scotland or Wales) only 11.7% – some 214 ed. There will be specific areas where these concrete traffic accident fatality remains greater on roads with a miles – currently have concrete barriers to barriers aren’t suitable and where alternative barriers and higher speed limit, statistically you’re still less likely to be the higher H2 standard. An additional 1.7% safety fences may be more appropriate.” involved in an accident on a motorway. In 2010, 71% of ▲ Standard use of a Concrete Step Barrier central reserve (31 miles) is made up of non-stepped Highlighting recent work on the M4, an HA spokesman casualties occurred on built-up roads compared to 24% on DfT-designed concrete barriers on the M25. insists: “We issued a press notice recently [see box] non-built-up roads and 5% on motorways. The limitations of N2 barriers have not been lost on The remaining 86.6% (1,578 miles) is made explaining where we’re putting in concrete barriers. We are But when things do go wrong on a motorway the results engineers and safety experts. Doubtless it was one up of metal barriers of differing types. replacing steel barriers, but it’s where there’s a need to can be catastrophic, especially if an HGV smashes through of the reasons why in 2006 the Highways Agency (HA) In the UK the design rights to the Dutch replace them rather than taking out perfectly useful steel the central barrier straight into the oncoming traffic. Thank- confirmed that ‘high containment’ concrete central barriers Step barrier are held by Britpave, the barriers and replacing them with a concrete one.” ■ fully, it’s a rare occurrence. However, the likelihood of an would be installed on all new motorways, and on those transport infrastructure group and trade HGV breaching the central bulwark is greatly increased by existing motorways where the metal barriers have reached association. Its commercial arm acquired them from the the fact that the current metal or wire-rope barriers used the end of their useful life. Dutch government and licenses their use to approved CONCRETE ACTION ON BARRIERS on most of the UK’s motorways and dual carriageways installation companies carrying out replacement barrier aren’t designed to withstand the impact of a 44-tonner A stronger barrier projects. Britpave director David Jones says the original As part of its current upgrade programme, the HA has begun replacing travelling at 85km/h. Their N2 specification only requires a Concrete barriers have a number of advantages. Their design has evolved, not least in the way it is surface-mount- existing metal barriers on the 2.5-mile section of the M4 between Junctions capability to contain a car weighing up to 1,500kg, striking service-life is double the current 25-year span of steel ed to the carriageway. The revised barrier design has also 14-15, near Baydon with concrete barriers. The work is due to be completed by it at a 20° angle, travelling at a speed of up to 110km/h… barriers. More importantly, from a road safety perspective, been renamed the Britpave Concrete Step Barrier. February 2012, and according to the agency: “This section of metal barrier has certainly not a fully laden artic. their H2 specification is more stringent, as they must be “Concrete barriers have been developed to prevent that reached the end of its maintainable life. Concrete barriers are immensely strong, capable of containing a vehicle weighing up to 13 tonnes. most dangerous of motorway accident – the crossover,” and reduce the likelihood of a vehicle crossing the central reservation and “Concrete barriers have been developed That improved performance, says the HA, “reduces the says Jones. “Recognising their safety benefits, the HA has reaching the opposite carriageway.” Concrete step barriers have also been likelihood of a vehicle crossing the central reserve and begun a programme of replacing steel with concrete where used on sections of the recently-upgraded A421 in Bedford. To find out more and tested to prevent that most dangerous reaching the opposite carriageway”. Concrete barriers also motorway traffic exceeds 25,000 vehicles per day.” about Britpave go to http://www.britpave.org.uk/defaultCSB.ink motorway accident – the crossover” need less remedial work (if any) after an impact, so While H2 barriers only need to stop vehicles up to 13

44 COMMERCIAL MOTOR 5/1/12 For today’s news visit: www.commercialmotor.com For today’s news visit: www.commercialmotor.com 5/1/12 COMMERCIAL MOTOR 45

CMO_050112_044-045.indd 44-45 19/03/2012 17:31:56