NO doubt many motorists driving late at night or in the early hours along almost-deserted motorways have been struck by the vast amount of energy being spent to keep the carriageways lit when so few vehicles are using them.

Mile after mile of overhead lights blaze away redundantly in those long, empty hours when almost everyone is asleep.

But they burn for the sake of road safety -- against which the high price of so much wasted energy has to be set... until now.

For East Lancashire's M65 motorway is now the first in the country with lighting that shines with logic. It works on the smart but simple principle of the lighting dimming as the traffic decreases and brightening as it increases.

The system uses the electronic sensors which are already installed at the sides of the motorway to count the flow of vehicles. Now, they have been linked to the lighting to make it respond accordingly -- though even at the lowest traffic levels, the lights stay bright enough to aid drivers.

The savings on energy costs are bound to be immense. But they are far from the only benefits being reaped through this first introduced by Lancashire County Council.

Less carbon dioxide is pumped into the atmosphere by power stations as the demand for energy drops as the lights dim. Extended nationwide and beyond, the environmental advantages could be tremendous.

Nor is this the only green gain -- so-called light pollution is also cut and there is less intrusive glare for residents living within sight of the motorway to endure.

And it is also believed health and road safety benefits may arise from the system -- as research taking place suggests that it could lead to a reduction in driver-fatigue that is thought to be brought on by travelling under a continuous line of bright lights when there are no other distractions.

The project is so simple and clearly advantageous that, now, it seems a wonder why it was not thought of long ago. But with so many economic and environmental advantages, its brilliance makes it clear that East Lancashire will show highways authorities everywhere which road to follow.