Akis Theofilatos has successfully defended his PhD thesis titled: An advanced multi-faceted statistical analysis of accident probability and severity exploiting high resolution traffic and weather data. This PhD thesis was carried out at the Department of Transportation Planning and Engineering at the School of Civil Engineering of the National Technical University of Athens under the supervision of Prof. George Yannis.
The objective of this PhD thesis is the investigation of accident probability and severity exploiting high resolution traffic and weather data from urban roads and motorways, collected on a real-time basis, with specific focus on Powered-Two-Wheelers. For that purpose, an advanced mesoscopic multi-faceted statistical analysis was conducted in order to expand previous road safety work and contribute to the further understanding of the complexity of accident probability and severity. Linear and non-linear models were developed on the basis of 6-year accident data from urban roads as well as an urban motorway in Greater Athens area (Attica Tollway). Empirical findings indicate that high resolution traffic and weather data are capable of opening new dimensions in accident analysis in urban roads and urban motorways. The multi-faceted statistical analysis conducted in the thesis has revealed a consistent and strong impact of traffic parameters on accident probability and severity. It is interesting that weather parameters were not found to influence accident probability and severity when linear relationships are considered, however, the application of cusp catastrophe models demonstrated that it is likely that even small traffic and weather changes may have a critical impact on road safety in urban roads as sudden transitions from safe to unsafe conditions (and vice versa) may occur, especially for PTW traffic.