Trrl Lr 780

The experiment consisted of installing traffic islands in the minor road approaches, extending minimally to the left of the centre lines so as to discourage driving straight through the intersections, and to alert drivers, causing them to take appropriate action. Analysis of accidents reported over periods of four years before and four years afetr installation of the islands showed a significant reduction of 49 per cent of the total of accidents which would have been expected after allowing for external changes. The total cost atributable to the experiment is estimated to have been Å“19,000. During the 'after' period of four years (1972-5) the saving of accidents is conservatively estimated to have been 5 fatal, 15 serious and 20 slight injury accidents, representing a saving of Å“200,000 at 1972 prices