The Effects of Seat Belt Legislation on British Road Casualties: A Case Study in Structural Time Series Modelling

摘要: Monthly data on road casualties in Great Britain are analyzed order to assess the effect casualty rates of seat belt law introduced January 31, 1983. Such analysis is known technically as intervention analysis. The form that used this paper based upon structural time series modelling and differs significant respects from standard ARIMA modelling. relative merits two approaches compared. Structural techniques estimate changes for various categories users following introduction law. We first note high rate compliance with By February 1983, wearing had jumped 90 percent has remained at approximately 95 March 1983 onwards. There can be no doubt success regards compliance. In considering figures we distinguish between those directly affected by law, namely car drivers front passengers, not rear pedestrians cyclists. Taking numbers killed seriously injured (KSI), found a reduction 23 30 passengers. Thus, there have been substantial reductions. For passengers KSI rise 3 percent, fall one-half cyclists an increase 5 -- all three these values being statistically insignificant. conclude evidence change affected. killed, 18 25 However, indirectly our model gave 27 8 pedestrians, 13 value highly other borderline significance. was fatalities unable provide completely satisfactory explanation difference article contains pages comments discussants authors' response. Language: en