Abstract
The purpose of this study has been to assess the effects on road safety of various measures introduced in signal controlled intersections. Before and after analyses have been carried out for 29 intersections in which signals and /or markings were changed during 1978- 1981. The measures been studied were: (1) control of left turns by red- amber- green arrow signals (2) control of flows (3) simplified signal programmes (4) intergreen (5) changes of road marking (6) improvement of both road markings and signals, and (6) introduction of left turn arrows.