Tunnels are very dark and you need a lot of lighting to keep drivers safe. Despite this, most of the roads in the UK use a black asphalt road surface that absorbs so much of the light, especially in the tunnels. Bright-coloured asphalt has been found to reflect more light and make the tunnels brighter with fewer lights and less power therefore being needed.
Why use Asphalt in the first place?
Ordinary asphalt is made with bitumen that comes from crude oil. It is great for road construction as it’s flexible, durable, is good for traction and easy to repair. It is however black in colour and absorbs a lot of light.
What about light coloured asphalt?
We can use light-coloured asphalt or white asphalt which can be made by adding blanc bitumen or synthetic white resin to the asphalt mixture. This light-coloured asphalt will reduce the cost of illumination in tunnels.
When light-coloured asphalt was tried in tunnels throughout Europe it was found to really save money. When tried in Geneva, Switzerland, it saved between 30 percent and 40 percent of the cost of lighting in the Confignon Tunnel. In Luxembourg, it was found that there could be a cut in the number of lights, helping to cut annual energy costs by 39,000 euros in just one tunnel.
In the UK, the use of coloured asphalt is more widespread. The coloured asphalt surfaces are commonly installed for use on roads, car parks, drives, sports courts and many other outdoor landscaping applications. In North America, coloured asphalt is used mostly to separate different kinds of traffic areas, like bicycle or pedestrian and traffic lanes. It is also used as a decorative material for rejuvenating areas that would otherwise appear dark and boring.
Conclusion: Using Light-Coloured Asphalt on Roadways
Although the potential of light-coloured asphalt is not fully recognised in North America, in Europe, light-coloured asphalt is now being used in tunnels. This makes the roadway lighter which reduces the cost of lighting the tunnels. The next step is to use light-coloured asphalt all over UK surface roads, which could reduce the cost of night-time road lighting as well!