I’ve never been fond of driving at night, especially on long stretches of unlit country roads. I’ve always been suspicious that any number of wild animals might, at any moment, leap out from the dark wilderness and into the path of my car causing me to swerve violently into oncoming traffic.

So I was somewhat concerned when I read that a series of reports from the County Surveyors Society (CCS) has proposed that local councils might like to consider dimming the lights on our highways and residential areas to save money and cut down on CO2 emissions.

To my mind, this isn’t the safest of proposals. Dimming the lights might be good for the bank balance and the environment, but does little to enhance the safety of the poor driver who has to negotiate the freshly darkened road.

What I’d prefer to see instead is a technical solution to this issue that could retain the light levels that we already have while reducing the amount of power required.

Unsurprisingly, one such solution already exists. And across parts of Europe, its use has helped to reduce lighting costs and emissions as well as improve driver visibility without compromising safety. The solution is simple enough too. Rather than use traditional black-top, our cousins in Europe have deployed light asphalt surfaces instead.

In the Confignon Tunnel, near Geneva, Switzerland, for example, field trials showed that one spotlight out of two could be turned off because of the increased luminance of the light asphalt surfacing. In that project, savings made on lighting meant that additional capital costs for the resurfacing work were recouped within just four years.

James Freeman, the national special products manager of materials supplier Tarmac, believes that here in the UK local authorities could also examine how such surfaces might be used before hitting the ‘dimmer switch’.

Freeman says that the light-coloured asphalt is just as durable as the traditional ”black top’, so there are no additional reliability concerns with its use. What is more, adding quartzite aggregate, light coloured pigments and high-quality polymers with binders to enhance the mechanical stability of the asphalt mix ensures that it is suitable for all heavy trafficked areas.

Sadly, Freeman says, in the UK, the full potential for the light-coloured asphalt has not been realised. Typically, it has been used to demarcate areas such as bus and cycle lanes. But clearly, it could also be used to surface all manner of roads in tunnels, at intersections and roundabouts, as well as on the approach to junctions on unlit rural roads.

Whether the cost of deploying such materials will be viewed as a long term investment by those responsible for lighting the roads in the UK, however, is another matter entirely. If I’m not mistaken, it’s more likely that the quick fix, lights out option is the one that is likely to be considered first.
This comment was originally published in the Engineeringtalk Newsletter