§ Mr. Rostasked the Secretary of State for Energy what has been the annual fuel saving resulting from the 60 m.p.h. speed limit.
§ Dr. John A. CunninghamSpeed restrictions are one of a number of factors affecting motor spirit and diesel oil consumption. These include driving habits, size and efficiency of motor vehicles, mileage travelled by different types of vehicles and road conditions. We cannot, however, on the basis of the evidence available, distinguish between all the individual effects and cannot, therefore, say what the direct effect of the 60 mph speed limit has actually been. In order to obtain some idea of the effects of speed limits, however, it has been estimated that, on the basis of all the relevant information, such as the mileage travelled on different roads and at different speeds by different vehicles, and according to the relationship between vehicles, speed and fuel consumption, a reduction of 5–10 mph would need to be achieved on all roads subject to the existing 50 and 60 mph limits, in order to effect a petrol saving of 1 per cent.—about 150,000 tonnes per year.