Abstract
Analyses have been made of the data on road widths obtained as part of the 1300 point traffic survey. The data are examined in relation to traffic flow data at the same sites and to similar width and flow data obtained in 1957-60 during the 1100-point survey. The results include: I. an estimate of the amount of widening and the expected tendency for it to be concentrated on to the busier roads and the more important class of road; II. a slight effect of high flows on narrow roads in limiting traffic growth; III. the substantial extra traffic growth found on roads that have been widened. IV. the considerable increase in the amount of road and high flows in relation to their widths.