Abstract
This report discusses the results obtained on the speed, flow and close-following of vehicles using the M4 motorway during peak traffic flow periods at Easter 1966 and at comparable times one month later. The results indicate that it may be possible to predict the degree of close-following behaviour from traffic flow but more data will have to-be obtained under various conditions before a complete analysis can be carried out, and it is proposed to continue monitoring M4 traffic for this purpose.