Identification of road user related risk factors

Deliverable 4.1 of the H2020 project SafetyCube


Talbot, R.; Aigner-Breuss, E.; Kaiser, S.; Alfonsi, R.; Braun, E.; Eichhorn, A.; Etienne, V.; Filtness, A.; Gabaude, C.; Goldenbeld, C.; Hay, M.; Jänsch, M.; Leblud, J.; Leskovšek, B.; ....; Van Schagen, I.; et al.



Safety CaUsation, Benefits and Efficiency (SafetyCube) is a European Commission supported Horizon 2020 project with the objective of developing an innovative road safety Decision Support System (DSS). The DSS will enable policy-makers and stakeholders to select and implement the most appropriate strategies, measures, and cost-effective approaches to reduce casualties of all road user types and all severities.

This document is the first deliverable (4.1) of work package 4 which is dedicated to identifying and assessing human related risk factors and corresponding countermeasures as well as their effect on road safety. The focus of deliverable 4.1 is on identification and assessment of risk factors and describes the corresponding operational procedure and corresponding outcomes. The following steps have been carried out:

  • Identification of human related risk factors – creation of a taxonomy
  • Consultation of relevant stakeholders and policy papers for identification of topic with high priority (‘hot topics’)
  • Systematic literature search and selection of relevant studies on identified risk factors
  • Coding of studies
  • Analysis of risk factors on basis of coded studies
  • Synopses of risk factors, including accident scenarios

The core output of this task are synopses of risk factors which will be available through the DSS. Within the synopses, each risk factor was analysed systematically on basis of scientific studies and is further assigned to one of four levels of risk (marked with a colour code). Essential information of the more than 180 included studies were coded and will also be available in the database of the DSS. Furthermore, the synopses contain theoretical background on the risk factor and are prepared in different sections with different levels of detail for an academic as well as a non-academic audience. These sections are readable independently.

It is important to note that the relationship between road safety and road user related risk factors is a difficult task. For some risk factors the available studies focused more on conditions of the behaviour (in which situations the behaviour is shown or which groups are more likely to show this behaviour) rather than the risk factor itself. Therefore, it cannot be concluded that those risk factors that have not often been studied or have to rely more indirect and arguably weaker methodologies, e.g. self-reports , do not increase the chance of a crash occurring.

The following analysed risk factors were assessed as ‘risky’, ‘probably risky’ or ‘unclear’. No risk factors were identified as ‘probably not risky’.


  • Influenced driving – alcohol
  • Influenced Driving – drugs (legal & illegal)
  • Speeding and inappropriate speed
  • Traffic rule violations – red light running
  • Distraction – cell phone use (hand held)
  • Distraction – cell phone use (hands free)
  • Distraction – cell phone use (texting)
  • Fatigue – sleep disorders – sleep apnea

Probably risky

  • Risk taking – overtaking
  • Risk taking – close following behaviour
  • Insufficient knowledge and skills
  • Functional impairment – cognitive impairment
  • Functional impairment – vision loss
  • Diseases and disorders – diabetes
  • Personal factors – sensation seeking
  • Personal factors – ADHD
  • Emotions – anger, aggression
  • Fatigue – Not enough sleep/driving while tired
  • Distraction – conversation with passengers
  • Distraction – outside of vehicle
  • Distraction – cognitive overload and inattention


  • Functional impairment – hearing loss (few studies)
  • Observation errors (few studies)
  • Distraction – music – entertainment systems (many studies, mixed results)
  • Distraction – operating devices (many studies, mixed results)

The next step in SafetyCube’s WP4 is to identify and assess the effectiveness of measures and to  establish a link to the identified risk factors. The work of this first task indicates a set of risk factors that should be centre of attention when identifying corresponding road safety measures (category ‘risky’).

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