The relation between the speed of passenger cars and risk of involvement in a severe crash in an urban setting, using a case-control study was studied. "Cases" were 45 vehicles involved in severe crashes in the Adelaide metropolitan area; the pre-crash speeds were determined using accident reconstruction techniques. For each case, the speeds of 10 controles were measured, using an amphometer: controles were cars not involved in crashes that passed through the crash location at the same time of day, day of week, and season. The risk of involvement in a severe crash increased as vehicle speed increased. In particular, within 60 km per hour zones, compared with vehicles traveling at about the posted limit, vehicles traveling at 75-84 km per hour had an odds ratio of 7.8 [95% confidence interval (CI) = 1.4 -38.8] for a severe crash, whereas vehicles with speeds in excess of 84 km per hour had an odds ratio of 39.0 (95% CI = 9.3 -170.5)
Abstract