title: Road safety forecasts in five European countries using structural time series models.
abstract: OBJECTIVE
  Modeling road safety development is a complex task and needs to consider both the quantifiable impact of specific parameters as well as the underlying trends that cannot always be measured or observed. The objective of this research is to apply structural time series models for obtaining reliable medium- to long-term forecasts of road traffic fatality risk using data from 5 countries with different characteristics from all over Europe (Cyprus, Greece, Hungary, Norway, and Switzerland).
  
  
  METHODS
  Two structural time series models are considered: (1) the local linear trend model and the (2) latent risk time series model. Furthermore, a structured decision tree for the selection of the applicable model for each situation (developed within the Road Safety Data, Collection, Transfer and Analysis [DaCoTA] research project, cofunded by the European Commission) is outlined. First, the fatality and exposure data that are used for the development of the models are presented and explored. Then, the modeling process is presented, including the model selection process, introduction of intervention variables, and development of mobility scenarios.
  
  
  RESULTS
  The forecasts using the developed models appear to be realistic and within acceptable confidence intervals. The proposed methodology is proved to be very efficient for handling different cases of data availability and quality, providing an appropriate alternative from the family of structural time series models in each country.
  
  
  CONCLUSIONS
  A concluding section providing perspectives and directions for future research is presented.
authors.affiliation: a Laboratory of Transportation Engineering , National Technical University of Athens , Athens , Greece.
authors.forename: Constantinos
authors.initials: C
authors.lastname: Antoniou
authors.forename: Eleonora
authors.initials: E
authors.lastname: Papadimitriou
authors.forename: George
authors.initials: G
authors.lastname: Yannis
mesh_terms: D000063:Accidents, Traffic / Q000401:mortality*; D005060:Europe / Q000453:epidemiology; D005544:Forecasting; D006801:Humans; D015233:Models, Statistical; D012449:Safety / Q000706:statistics & numerical data*; D013997:Time Factors
keywords: Europe; latent risk time series (LRT) models; road safety; state-space models; structural time series models