Developing a Safety Risk Model

Risk Solutions has developed a comprehensive Safety Risk Model that analyses the risks to road users, road workers and Traffic Officers associated with the operation, maintenance and improvement of the Strategic Road Network (SRN) in England.  In addition, the model can analyse the safety risk profile on the SRN, identifying the main risks as well as their primary causes. The model is also being used to help Highways England assess the extent to which it can reduce risk by its own actions or by influencing other stakeholders.

The Safety Risk Model is used to identify the root causes, contributory factors and consequences of collisions involving particular types of vehicles/drivers or on particular road types.  In the course of developing the SRM, and earlier projects analysing road safety risks at particular locations or associated with new methods (such as the introduction of Passively Safe Gantries), we have established an in-depth understanding of a wide range of relevant databases and the skills needed to cleanse and join data, ensuring consistency and accuracy is maintained when data is sourced from the variety of different systems.

Data has been extracted from a wide range of systems, including:

  • STATS19 – police reports of road traffic collisions involving injuries
  • IRIS – the Traffic Officer’s Incident Reporting System
  • AIRSweb – the supply chain’s Accident and Incident Reporting System
  • HAPMS – the Highways Agency (England) Pavement Management System
  • NTIS – the Highways England National Traffic Information System, and prior to 2015


The SRM uses this data to calculate the statistical safety risk of travelling across the road network, and conducting maintenance and renewal work on the road network.  Safety risk is measured in terms of the number of incidents involving personal injury, the number of killed and seriously injured (KSI), and the number of fatalities and weighted injuries (FWI).  Safety risk is also normalised by the number of vehicle miles or kilometres driven on the Strategic Road Network to allow risk comparisons.

The SRM and its supporting data can be used to analyse the safety risk profile of the whole strategic road network over time, or individual schemes/roads/routes/areas, identifying the main risks as well as their primary causes. These analytics are used to compare safety risk between different types of road (motorway, dual carriageway, single carriageway), number of carriageway lanes, vehicle type, time of day, location, junction type.

This means that we are able to offer flexibility in using the model to answer a wide range of questions.  For example enabling risks associated with junctions to be better understood, using HAPMS link-based data to examine how different road characteristics affect risks, such as safety barriers, numbers of lanes, and adding flexibility to select individual road links for a more detailed analysis.

The results allow Highways England to gain deeper insights about where they should focus time and effort to improve safety for road users and workers, and to evaluate the effectiveness of their investment over time.

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