The D902 is a popular alpine road crossing the Alps between the main N91 Grenoble and Briançon highway to St Michel de Maurienne and passing through Valloire. One of the many highlights of this route are the magnificent panoramic views obtained from the highest point of the road at Col du Galibier at some 2645 metres above sea level.
Approximately 100 metres below the summit at Refuge du Galibier a road bypasses the summit through the narrow , single carriageway 374 meter long Galibier Tunnel. No traditional lighting is provided within the tunnel and traffic is controlled through the tunnel with traffic lights at each entrance.
This tunnel was closed to all traffic in 1976 due to its unsafe condition. After being closed for many years and then some extensive repair work it reopened on Friday 17th May 2002. The works carried out included renewal of the tunnel lining, kerbs, a new road surface and the installation of Astucia hardwired studs along the sidewalls to delineate the edge of the carriageway and tunnel walls.
The route over the Col du Galibier has always been popular with cyclists and the route is regular gruelling stage of the Tour de France. Its connection with the famous race is very much immortalised by a stone monument located nr the south portal of the tunnel dedicated to the glory of Henri Desgrange (1865-1940), former director of L'Auto newspaper, creator of the Tour de France.
Almost 100 Astucia D Series hardwired bi-directional amber studs were installed, mounted within the lower pre-cast concrete lining sections along the inside of the Galibier Tunnel. Located at regular intervals and approximately half meter above the kerb the studs with their built in Light Emitting Diodes (LEDs) provide increased awareness of the proximity of the tunnel walls for traffic in either direction. Traditional retro-reflectors also form an integral part of the studs further enhancing the effect. Owing to the fact that the tunnel is single bore and controlled by Traffic lights the studs also employ a strobe effect indicating the direction of travel as indicated by the traffic lights located at each end of the tunnel.
Drivers are literally guided though the tunnel with the Astucia D Series studs providing enhanced awareness of the proximity of the tunnel side walls which eliminates any optical illusions of distances that can be created by a vehicles headlights bouncing back off the concrete segments especially at the side of the vehicle. Also a linear guiding effect is created, focusing the drivers attention towards the middle of the lane, and therefore the positioning of the vehicle, and the tunnel exit.
