Kontrolldiagram för månadsvis uppföljning av antal dödade i vägtrafiken
2005 (Swedish)Report (Other academic)Alternative title
Control charts for the monthly follow up of the number of fatalities in road traffic accidents (English)
The number of fatalities in road traffic accidents and the number of fatal accidents are important indicators of the traffic safety situation. The monthly values are, however, difficult to interpret due to large random fluctuations. The aim of this project have been to develop methods that facilitates analysis and interpretation of these data. Control and prognosis charts are presented in the report. The control charts have an upper and a lower limit, and a value outside these limits can be interpreted as a real departure from the prevailing level. Control charts for monthly values are useful to determine if the outcome a specific month is unusually high or low. These diagrams are, however, not good at detecting small changes during a longer time period. They are therefore complemented by charts of the total number of fatalities from the beginning of the year. Prognosis charts are included as a complement to the control charts. These charts are based on so called ARIMA models and can be used for data with autocorrelation. At the beginning of each calendar year, prognosis and prognosis intervals are calculated for the entire year. An outcome outside the prognosis intervals is interpreted as a change in the prevailing pattern. Prognosis charts are applied to twelve-month moving sums of the number of fatalities.
Place, publisher, year, edition, pages
Linköping: VTI., VTI rapport 513 , 2005. , 42 p.
VTI rapport, ISSN 0347-6030
Accident rate, Fatality, Statistics, Month, Method, Analysis, Mathematical model, Correlation
Research subject Road: Traffic safety and accidents, Road: Collation of accident statistics
IdentifiersURN: urn:nbn:se:vti:diva-6379OAI: oai:DiVA.org:vti-6379DiVA: diva2:675256