§ Mr. Simon HughesTo ask the Secretary of State for the Environment what is the average emission of lighting above horizontal, as a proportion of output in(a) trunk road lighting and (b) other street lighting; if he will estimate the amount of electricity used per annum in lighting above horizontal; and if he will make a statement.
§ Mr. Kenneth CarlisleI have been asked to reply.
About 12 per cent. of the light output from most road lighting lanterns on trunk and other roads is reflected upwards from the road surface. It is this reflected light which provides safe visual conditions for drivers. It is estimated that about 2 per cent. of the light output from lanterns is reflected upwards by impurities in the air before it reaches the road surface and about the same proportion goes directly upwards.
It is estimated that some 2,000 million units of electricity are used each year for road lighting in Great Britain.