Evaluating road safety audit procedures: some questions and a new method of study

Abstract

This article discusses the current views on the application of road safety audits (RSAs) as a tool for the improvement of road safety and proposes a new method of study for detailed evaluation of some features that can influence their effectiveness. This is demonstrated in the practical setting of RSAs applied to existing road reviews or inspections. Starting from a review of published sources on RSAs in different countries, a set of questions has been identified and a case study undertaken on the impact of alternative RSA procedures on its overall effectiveness. RSA effectiveness is measured both as agreement with a safety expert assessment and to an accident-based study. The main features analyzed in the case study include the type of observer used for data collection and the type of checklist used as a guide to field work. Based on an exploratory study, the performance of RSA application is evaluated using weighted indices of concordance and disagreement, and the rating of detection or omission for the observations gathered in the accident diagnosis of the safety problems at the intersection studied, supplemented by a statistical analysis of the influence of selected covariates on these scores. The main results of the case study can be summarized as clear support to team work for field observation and also to employing less-experienced personnel for field observation. The study also stresses the need for procedures/criteria for priority setting. These conclusions are useful for the selection of alternative RSA procedures in agencies responsible for promoting or enforcing RSA and in professional teams carrying out RSA tasks. Several features deserving further study are also identified.

Keywords:

• road safety audits
• road safety reviews
• safety measures
• statistical analysis

Acknowledgements

We would like to thank the Traffic Engineering Company of the City of São Paulo for providing data and support for most of the work, the professionals who collaborated as observers in the field study, FAPESP (the Foundation for Research Aid of the State of São Paulo) that supplied the accident data and also especially Denise Lima Lopes and Veridiana Maria Armond Vasconcelos (who helped us in the data-processing tasks) and Cristina Borba (who helped us in the revision of a previous version of this article). The remaining errors are ours.

Disclosure statement

No potential conflict of interest was reported by the authors.

Funding

This work was partially supported by FAPESP-Foundation for Research Aid of the State of São Paulo, Brazil.