This report is the second of two planned publications of PIARC Task Force 4.1 “Road Design Standards” in the period 2020 – 2023. PIARC considered the importance of comparing international road design standards to check their updated status and the degree of their readiness to face the forthcoming innovations in road mobility.
The full report presents a review of selected models in the field of road design standards based on a literature review, which was the first publication of PIARC TASK Force 4.1. It is the first document in many years comparing models applied in road design standards from several countries. The document aims to compare selected models adopted in different countries and evaluate the possible need for their adaptation to the requirements of a rapidly changing world in the field of road transport systems (new technologies, changes in mobility modes, and availability of multiple diffused data sources). This report also assesses possibilities of transferring models to other road design standards mainly in Low- or Middle-Income Countries.
The comparison and conclusions were drafted based on the review road design standards collected among the members of Task Force 4.1. Ultimately, the comparison covered 18 countries, depending on the models, around the world: Australia, Austria, Belgium-Flanders, Belgium-Wallonia, Canada, Czechia, France, Germany, Hungary, Italy, Japan, Mexico, Poland, Portugal, Romania, South Africa, Spain, Ukraine, United States of America.
The full report focuses on reviewing the following models related to sight distance: stopping sight distance, overtaking sight distance, decision-making sight distance, as well as maximum and minimum grades for road profiles. A review of models is supported by detailed information from road design standards which is reported in the Appendix.
More details about road design standards, which were used for the comparison of selected models for road design are included in the literature review report "State of the Art in Road Design Standards (2022R22EN)" published in 2022.