Nordic Human Factors Guideline

by Gabriel Helmers


Nordic Human factors Guideline is a Nordic collaborative project under the Nordic Road Geometry Group. The project covers road user demands to the design and construction of road systems based on existing knowledge of road users’ physical and mental abilities.

The work is carried out by a Nordic research team represented by Lene Herrstedt (Civil Engineer, MSc., Ph.D., Trafitec, Denmark), Gabriel Helmers (Traffic Psychologist, Ph.D., Consultant, Sweden), and Fridulv Sagberg (Traffic Psychologist, Senior Researcher, TOI, Norway).

The project includes four sub-projects I, II, III, and IV:

I) Collection of existing knowledge based on comprehensive literature studies is presented in five thematic notes on road users’ physical and mental abilities:

  • Reaction time – break response time and resolution response time
  • Eye level, reading distance, and reading time for drivers
  • Walking speed
  • Assessment of speed and distance
  • Inattention and distraction

II) Development of an explanatory model for road user behaviour with the purpose of increasing the understanding of how drivers act in traffic and how our actions are influenced by road design and traffic environment. Conclusions from the model form the basis of ”The self-explaining road”.

III) Execution of a number of case analyses for verification of the applicability of the explanatory model as a tool for problem analysis and solution of specific traffic problems in practice.

IV) Three training sessions encompassing three power point series with accompanying notes for the dissemination of the main findings of the project.

This report describes the results of sub-project II) Development of an explanatory model for road user behavior. The report is written in Swedish by Gabriel Helmers with the assistance of Lene Herrstedt and Fridulv Sagberg.

The report is also available as download in English from Trafitec’s website All reports from the Nordic Human Factors Guideline project may be downloaded from

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