Accident Analysis and Prevention 60 (2013) 384–395 Contents lists available at ScienceDirect Accident Analysis and Prevention jo u r n al hom epa ge: www.elsevier.com/locate/aap Road safety performance indicators for the interurban road network George Yannis a,∗ , Wendy Weijermars b , Victoria Gitelman c , Martijn Vis b , Antonis Chaziris a , Eleonora Papadimitriou a , Carlos Lima Azevedo d a National Technical University of Athens, Greece b SWOV Institute for Road Safety Research, The Netherlands c Technion, Israel Institute of Technology, Israel d LNEC National Laboratory for Civil Engineering, Portugal a r t i c l e i n f o Article history: Received 30 December 2011 Received in revised form 9 August 2012 Accepted 17 November 2012 Keywords: Road safety Performance indicators Road network Pilot studies a b s t r a c t Various road safety performance indicators (SPIs) have been proposed for different road safety research areas, mainly as regards driver behaviour (e.g. seat belt use, alcohol, drugs, etc.) and vehicles (e.g. passive safety); however, no SPIs for the road network and design have been developed. The objective of this research is the development of an SPI for the road network, to be used as a benchmark for cross-region comparisons. The developed SPI essentially makes a comparison of the existing road network to the theoretically required one, defined as one which meets some minimum requirements with respect to road safety. This paper presents a theoretical concept for the determination of this SPI as well as a translation of this theory into a practical method. Also, the method is applied in a number of pilot countries namely the Netherlands, Portugal, Greece and Israel. The results show that the SPI could be efficiently calculated in all countries, despite some differences in the data sources. In general, the calculated overall SPI scores were realistic and ranged from 81 to 94%, with the exception of Greece where the SPI was relatively lower (67%). However, the SPI should be considered as a first attempt to determine the safety level of the road network. The proposed method has some limitations and could be further improved. The paper presents directions for further research to further develop the SPI. © 2012 Elsevier Ltd. All rights reserved. 1. Introduction In order to monitor the efficiency of road safety measures and road safety progress in general, the most common indicators are the numbers of accidents, fatalities and injuries. These numbers, how- ever, are often not sufficient to illustrate the level of road safety, as they depict the “worst case” of unsafe operational conditions of the road traffic system. Moreover, counts of accidents and casu- alties sometimes do not reveal the processes that produce them. Therefore, additional safety indicators are required for assessing the safety conditions of a road traffic system and for monitoring their progress (ETSC, 2001; Wegman et al., 2008). Road safety performance indicators (SPIs) are defined as meas- ures (indicators) that reflect the operational conditions of the road traffic system that influence the system’s safety performance (Hakkert et al., 2007). The SPIs’ purpose is to reflect the current safety conditions of a road traffic system; to measure the influence ∗ Corresponding author at: National Technical University of Athens, Department of Transportation Planning and Engineering, 5 Heroon Polytechniou Str., GR-15773 Athens, Greece. Tel.: +30 2107721326; fax: +30 2107721454. E-mail address: geyannis@central.ntua.gr (G. Yannis). of various safety interventions and to enable comparisons between different road traffic systems (e.g. countries, regions, etc.). SPIs may also provide information about underlying causes of accidents. They may concern particular groups of road users e.g. children, new drivers or professional drivers, or compliance with important safety rules e.g. seat belt use, or cover specific areas such as the urban road network or the trans-European network (EC, 2003). SPIs have been increasingly researched during the last years, with particular emphasis on methodological and data issues (Wegman et al., 2008; Assum and Sørensen, 2010). Moreover, there is a rapid development of composite indicators e.g. indexes which are a combination of individual indicators (De Leur and Sayed, 2002; Hermans et al., 2008; Gitelman et al., 2010), since the mul- tidisciplinary character of road safety implies that policymakers should take various influential factors into account. Within SafetyNet, a 6th FP European Integrated Project, safety performance indicators were developed for seven road safety related areas, namely alcohol and drug-use, speeds, protective sys- tems, daytime running lights, vehicles (passive safety), trauma management and roads (Hakkert and Gitelman, 2007). An exhaus- tive literature review on SPIs (SafetyNet, 2005) was carried out in the SafetyNet project, and demonstrated that there were no SPIs for road networks in use. However, based on the Sustainable Safety 0001-4575/$ – see front matter © 2012 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.aap.2012.11.012