Abstract
The problems caused by traffic in the ancient cities of developing countries are outlined. A study is then described which examined the effectiveness of improvements carried out at intersections in the city of Amman, Jordan. Before and after data were collected from eight at-grade, pre-timed, signalised and one grade-separated intersection that were modified from roundabouts. Data concerning a) traffic volumes, b) speed, c) accidents, d) costs and e) capacity were collected. The data were analysed using accident prediction models. The signalisation of intersections is shown to be cost effective and therefore preferable to a more expensive capital project.