Consequences of Traffic Casualties in Relation to Traffic-Engineering Factors - An Analysis in Short-term and Long-term Perspectives

Abstract: The over-arching objectives of this thesis were to formulate a method to describe the consequences of traffic casualties, and to explain the influence of different traffic engineering factors on these consequences for society and individuals over time. A more detailed objective was to examine whether available short-term indicators can be used to predict consequences in a long-term perspective. Other objectives were to create a better understanding of the multidimensional nature of traffic safety problems, to find out how to allocate resources and traffic safety measures, and to identify changes in traffic safety problems over time.

The study was based on one year of traffic casualties, 1991/92, in the admittance areas of five hospitals, in Karlshamn, Karlskrona, Lidköping, Lund and Umeå. The hospital data set held 2,915 casualties, while the police reported 1,722 killed and injured. Data were collected with an incidence approach, and in a public health perspective, i.e. including pedestrians injured in single accidents. On several occasions up to three years and five months after the accident, the injured answered postal questionnaires about the health situation and their care received.

All analyses involved both the police and the hospital data sets. The traffic safety problems were expressed in following indicators: killed and injured, hospital care, ISS (Injury Severity Score), length of hospital stay, and visits to a doctor or physiotherapist/nurse, length of sick leave and health loss (Rosser Index), and described in terms of average severities, total consequences, and distributions of total consequences. The effects of six selected traffic-engineering factors on these indicators of consequences were thoroughly analysed in short-term and long-term perspectives. Moreover, the potential of four traffic safety measures were examined. Among the available short–term indicators, the ISS and length of hospital stay within one month after the accident performed the best, although not very well in predicting the long-term consequences of traffic injuries.