The Danish Road Directorate has asked Trafitec to develop tools to describe road safety for alternative road design and traffic management when planning new motorways or redesigning existing motorways. Trafitec authored the report “Uheldsmodeller, sikkerhedsfaktorer og værktøjer for strækninger – motorvejsnettet” (Accident prediction models, accident modification factors and tools for segments – the motorway network), which describes the road safety of motorways, including how accidents are modelled and how safety is affected by changes in road design and traffic management.

This publication is a short and easy-to-read version of the report mentioned above as well as a user manual to a calculation tool, which estimates expected numbers of accidents and injuries for motorway networks of various design and traffic management.

The publication describes the division of the motorway network into 15 different segment types. Accident prediction models have been developed for each type of segment, which can be used to estimate the expected numbers of accidents and injuries. The recommended accident prediction models are presented. For the five most common segment types a number of accident modification factors, which describe how safety is affected by changes in road design and traffic management, are also presented. The five segment types are motorway links, exit diverges, entrance merges, exit ramps and entrance ramps.

The recommended accident prediction models and accident modification factors are included in the calculation tool, which is available via Vejdirektoratet.dk and Trafitec.dk. The calculation tool user manual is the last chapter of this publication.