Intelligent road studs aim to make roads safer

High-tech road markings are being used in a bid make roads safer in Europe as Patrick Smith reports Intelligent road studs are being installed on two of the busiest sections of the main roads heading towards the port of Dover in County Kent, south-east England.
Road Structures / February 9, 2012
Intelligent Road Studs
Astucia SolarLite intelligent road studs are safely guiding vehicles to the English port of Dover

High-tech road markings are being used in a bid make roads safer in Europe as Patrick Smith reports

Intelligent road studs are being installed on two of the busiest sections of the main roads heading towards the port of Dover in County Kent, south-east England.

Both stretches of the dual carriageway are prone to fog and mist, and to improve night-time road safety full-lane and edge delineation are enhanced using more than 21,000 Astucia SolarLite F series embedded studs.

The units, with built in solar-powered LEDs (light emitting diodes), are being installed by 707 Clearview Traffic Group's contracting team for the 1441 UK Highways Agency via its managing agent contractors 1530 Balfour Beatty Mott MacDonald JV. [Astucia is one of Clearview Traffic's three brands].

The A20 road links the end of the M20 motorway with Dover, and is routed via the cliff top, and incidents have regularly occurred on this 10km route. Within a conservation area, alternative measures, such as traditional street lighting, were not viable or cost effective options. The 21km stretch of the A2 from its junction with the end of the M2 motorway also suffers from fog and mist.

The SolarLite intelligent road studs automatically illuminate from dusk to dawn and provide drivers with up to 900m of visibility, which Astucia says is ten times greater than the traditional, retroreflective, passive road stud which is limited by the headlight beam of the vehicle.

"A number of local authorities with existing installations in the UK have reported significant reductions in night-time accidents of well over 70% since the installation of the Astucia SolarLite intelligent road studs," says Astucia.

In Poland, 2489 Lunaro, the Astucia partner, recently installed similar studs in a number of locations including on the National road No 2 running between Poland and Belarus. The route, used daily by thousands of drivers, regularly has dangerous situations, and the installation of over 260 embedded studs aims to provide drivers with advance warning of slowing islands.

The most recent installation by Lunaro is of over 200 studs on National Road No 60 near Gostynin City, again helping to improve driver safety when near speed restrictions.

Laser beam

According to Per Kristian Røren Lien, project manager for laser system development at Norwegian company 2488 Electronova, in-road LED lighting equipment has very high visibility.

"It is easy to create lines to follow or lines that should not be crossed. The system described here is creating the same effect, but with a different technical approach," says Lien who has compiled a fuller paper on the system with co-author Petter Bergersen, of the Road Authority.

The E18 Bjørvika two-tube, 4,500m long highway tunnel in the Norwegian capital Oslo links two existing tunnels together into one continuous tunnel.

During the maintenance and safety analysis it became clear that a system was needed to divert traffic away from parts of the tunnel system to be able to sustain the necessary maintenance schedule.

"The answer was two gates between the two traffic directions to divert traffic into bi-directional traffic in one tube. It was decided that there was need for a stronger visual aid than normal for this application.

"Several alternative solutions were visualised and the visual impressions were evaluated by the tunnel construction project management group. It was decided that a clean and simple visual expression was the solution, so an in-road installation would be preferable.

"Salt and exhaust gases in the submerged tunnel will corrode most materials in a few years. Studded tyres wear down everything but the hardest of materials very quickly. LED in-road systems have been tested in this environment before, but the results have been everything but positive. The idea was to use a controlled beam of yellow light to hit the road surface and make a bright spot, instead of the LED installation in the ground.

"A laser was used for testing with white stone discs, white road marking paint and two different reflectors. It was observed there was much higher visibility with the reflectors than with the alternatives. Special reflectors were designed and manufactured in four different materials for durability testing. The most durable of the alternative materials proved to be a heat-treated nickel-chromium alloy.

"Light sources and control systems are safely placed in an electrical installations room. An optical fibre carries the light from the lasers out into the tunnel. Lens assemblies in the roof of the tunnel generate the correct laser beam shapes on the reflectors in the ground. The result is a very visible line of points on the road.

Retained retroreflectivity

Following its introduction in 2008 the new approved Stimsonite Model 980 road stud, marketed by 1394 Ennis Prismo Traffic Safety Solutions (see below), has been adopted by many highway engineers.

Over the past 18 months the stud has been installed on UK highways including in Durham, Redcar and Cleveland, the A1 and A1M, the A66 Scotch Corner-Kirby Stephen in northern England; all motorways between central Nottingham and Grantham; motorways in the north-west and the Midlands, and the motorways M180, M18, M62, the M25 and the new A27 Devils Dyke scheme in southern England. In early 2009, a substantial number of the studs were also laid as part of the widening scheme on the M1 motorway, between junctions 6 and 10 north of London, with proven excellent retention.

"In original BSI road trials, Stimsonite Model 980 exhibited a remarkable retained retroreflectivity and 100% location retention over a one-year period, which was significantly higher than that normally anticipated, or generally demanded for such road safety devices," says Ennis Prismo.

"It exhibited 409mcd/m²/lux of retained retroreflectivity after one year, more than twice that required by BSEN 1463 R1, which demands a minimum of 150mcd/ m²/lux for such surface applied markers." The Stimsonite Model 980 is supplied as a stick-on system incorporating a specifically-designed polymer-modified bitumen (PMB) adhesive proven to perform above minimum requirements of BSEN 1463 S1. The adhesive is supplied in three grades (tropical, semi-tropical and standard) to suit all climatic conditions. The stud complies fully with BSEN 1463, parts 1 and 2, is manufactured to ASTM D4280 and is approved for use by the UK highway authorities.

"It is manufactured from extremely tough, injection-moulded, high impact-resisting polymers and incorporates the most advanced air gap prismatic lens technology, protected by a highly abrasion resistant glass face. Its 17cm reflective area includes a 35° reflecting face that will continue functioning even if subject to damage." Ennis Prismo also reports that the 'inset' version, the Stimsonite Model C80/381, has also been successfully employed in Durham, Redcar and Cleveland and has just been introduced on motorways the north-west and the Midlands.

This model combines the durability of the injection moulded Model 80 series with a proven long life abrasion-resistant coating. The lens is set into an iron casting to protect it from snowplough operations and to ensure a positive interlock with the road.

"The result is a road stud that offers excellent adhesion, durability and retained reflectivity. The C80/381 is CE certified to meet EU Standard EN-1463:1997 for quality (Rated R1 for Reflectivity and S1 for Retention)," says Ennis Prismo, which recently underwent a rebranding.

Prismo Road Markings Limited, the global manufacturer and contractor of road markings and surfacings, is now rebranded as Ennis Prismo Traffic Safety Solutions.

All company operations are fronted by a new logo and web address (<%$Linker:External000oLinkExternalwww.ennisprismo.comEnnis Primofalsehttp://www.ennisprismo.com/falsefalse%>) with the new branding bringing the business closer in line with its parent company Ennis Traffic Safety Solutions.

Ennis is among the leaders for road markings in the USA as well as operating in the Asia Pacific region. Prismo enjoys a similar position in the UK and the Europe/Middle East/Africa region.

The branding enhancement is the culmination of a series of international business acquisitions that have significantly expanded Ennis' global trading activity.

Jonathan Fish, Ennis Prismo's marketing manager said: "This re-branding is simply a further step towards establishing the company as a truly global business, providing an unrivalled range of traffic safety solutions."

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