a comprehensive survey of speeds of cars on motorways was carried out in early autumn, 1976, using duncan's two-speed method: the measurement techniques are described in detail. similar surveys in 1970 and 1973 had shown an increase in speed, confirming a long-established upward trend. but the results obtained for 1976 - mean speed of cars 66 1/2 mile/h, with 36 per cent exceeding the 70 mile/h limit - were the same as those for 1973. this is attributed to the effects of the petrol crisis of 1973-74, which led to a doubling of the price of petrol at the pumps in the three years between the 1973 and 1976 surveys. it is concluded that, if petrol prices maintain their present level, the upward trend in speeds on motorways (and perhaps on other rural roads) may be over.(a)

Want to know more about this project?